imo basically first choose your floor. you can get into the details a lot with stopping power and penetration and fbi tests and whatnot but basically it gets into what are you comfortable and confident in to get the job done without more that would be hard to control or bulky or expensive. i think for most people, that's between .380 ACP/.38 and 9mm, and personally I always want to use something larger, so that's 9mm for me. i think .45 is harder on my wrist during practice, harder to mitigate recoil and isn't really necessary for anything less than bears, which makes it not as attractive to me, although some people really want and desire .45 in a self protection pistol. even though to me, pocket pistols are consumable, one time use devices, i still care about them a lot because imo they need to be small enough/less of a pain so that you will actually carry it everyday and practice with it often. for that reason i like to recommend the smallest gun that you feel like you can shoot accurately and competently, and that doesn't have to be the smallest possible gun in the caliber you want that is on the market necessarily. the first gun i ever bought actually was a sig p365, and while I enjoyed starting with that gun even if it wasn't necessarily the best first gun, I eventually found that the springfield hellcat for somehow being an extremely similar gun, was much easier to shoot for my hands, so i really like my hellcat. i would say that most people besides boomers nowadays should be using red dots for ease of sight acquisition, so unless you have extensive experience using irons, i would say that a red dot is almost mandatory. but the best part about these modern micro-compacts as they're called is that lots of them are optics ready, and some even support even fancier features like threaded barrels if you ever want to put a suppressor on it for some reason, although that would be basically impossible to carry every day effectively. while I think most people would find hip or back carry to be the most comfortable, the most effective carry location for draw speed is appendix, but the problem with appendix carry is usually ergonomic with people not liking it. even though i wear clothes with belt loops the majority of the time, I use the phlster enigma almost every day to carry a firearm independent of my belt loops, which I think lets me position the firearm effectively independent of the waistline on your pants and without needing a bulky gun belt that can print (show through clothes), and I would recommend it even if you're not a woman needing to work around different clothes just for the flexibility and comfort. so then once you've finally porchased a gun and several items like a phlster enigma or a belt, you'll need to get a holster to go with it. there are lots of different features to holsters such as the clip style (i use DCC monoblocks) and overall shape that many people have opinions on and such, I think the only thing that matters is that it's made out of kydex. it's a hard material that will basically keep the gun in a safe position as long as it's inside of it, as opposed to materials like leather or god forbid, fabric that could lead to a trigger getting mashed from debris or external forces. in my opinion kydex is an absolute requirement, but the rest is all personal taste and what works well for your setup and where you want to position the gun. phlster has a great playlist on youtube that describes what you should be looking for when trying to conceal carry, including finding the best location for concealment and i'd recommend watching those videos. anything that isn't a kydex holster secured to your body is a liability imo, i would greatly discourage other conceal carry "solutions" such as a free holster sitting in a pocket (no retention means you need two hands to draw a gun out of the holster, and the non-secured location means that the gun can differ in position and make it much harder to draw reliably) or purse carry (guns are very sensitive, so keeping a gun off your body is a high risk for theft or misplacement imo. reliable drawing requires that the gun be in the same location every time, and a purse is not connected to your body, giving that extra difficulty in drawing, orders of magnitude longer and harder than an item that is reliably indexed to somewhere on your body, like appendix, hip, back, thigh, etc. finally, even without a specialized bag designed to have a separate pocket/access to a firearm held in a repeatable off-body location, there is still the risk of the bag holding other items that could cause the firearm to enter non-safe positions, like if a pencil gets into the gun pocket, and you shove your gun in the gun pocket, and the pencil pushes into something soft like leather and causes the trigger to pull, etc. i know i'm making a big deal of the distance and repeatability of access to a firearm, but in situations with violence, violence usually shows up in real life completely unpredictably. there are lots of videos online about self defense encounters and violence, and while some recordings may show warning signs that we may have the comfort of analyzing from relaxed positions in our homes, violence should be though of happening like a speeding car racing around a corner to tbone someone in a red light, or a deer jumping out from behind trees onto the road with split seconds to react. in those situations, every half second of fumbling around to access a gun matters just as much as being able to swerve the car a moment earlier to avoid a catastrophic collision. this is why i am extremely critical of apparel created without much thought that would require lots of fumbling and searching, and why i consider the bar for a quality conceal carry setup to be so high to be done right. just shoving a gun into a bag with shit in it pointing every which way is such a huge liability you should probably be beat in the street with hammers, don't do that. anyways, supposing that you've got a setup that you like in the mirror that conceals well and you're happy, now starts the real important part that most people do not follow up on, but is probably the most important, which is repeated dry fire, and range practice. i'm glad that people who conceal carry have decided to accept and take on the responsibility of their own self-defense, but that requires that the person maintains ample ability as to not be a liability in an actual event, as it would be beneficial in that scenarios (and most scenarios actually) to instead of focus on other actions like getting out of there as fast as possible instead. I'll talk more about this later. but for practical purposes, such as while driving a car requires you to have the personal responsibility to ensure that your driving skills are competent and effective, you should be equally and if not much more competent with skills of drawing from concealment, in various clothes (jackets, hoodies, multiple shirt layers, whatever you wear normally), as well as usual firearm fundamentals which are made more challenging in general with smaller conceal carry handguns. usually this is recommended with regular dry fire practice where a gun is safely unloaded, moved to a different location where all ammunition has been completely cleared from the area, and then the firearm is drilled at targets in different scenarios, also potentially from different motions (walking, sitting, standing still, etc). however, even with diligent home practice, real life situations can be as different as sim racing at home can be to actually driving a race car. for that reason, standard range practice with real life rounds for recoil management is a must, and ideally, conceal carry classes that re-enact real life scenarios (such as like someone walking up to you while asking you lots of questions that may confuse you, etc) are highly recommended as they will give you much better experience than just calmly standing at a gun range and shooting items might give you. and even then, you will still have the knowledge that you are in a class and scenarios like this will be happening, which will not be a courtesy given by someone doing the same thing to you in real life. anyways, with all of that mentioned, there is a wider conversation about self-defense that should be had as well. a conceal carry permit class should have been acquired before even getting a handgun for conceal carry, probably using a first handgun that I'm assuming that you have already since conceal carry shouldn't be the first thing you attempt to do when getting into guns at all. but a conceal carry class will talk about legalities as regarding to your state and general practices, but may not even include best practices such as how to de-escalate situations effectively, other preparations besides firearms for self-defense, and how to manage your lifestyle to decrease risk in the first place (or even just about basic things like exercising regularly to keep yourself in good shape in case you need to book it from somewhere. a good exercise routine or youtube video about situational awareness is vastly better self-defense prevention than any difference a better holster clip could ever make). these are all incredibly important and may need to be researched/drilled from other sources, but personally this is how i approach things: be very comfortable with asserting yourself, embarrassing yourself if you even begin to feel like a situation begins to present risk. for instance in one scenario, i confidently raised my voice at a homeless person approaching me at like 3 in the morning at deserted gas pumps for instance, while simultaneously positioning my body in a secure, non-threatening stance, and calmly but firmly asking for the person to stop approaching me, and that was like the worst encounter i've had so far. i many other scenarios, i would've given that person cash without judgement or fuss, but in that scenario where i was traveling in the middle of the night on the outskirts of a town with nobody else around, the situation was different. however, before then, i evaluated my risk by choosing a gas station with lots of space around, with minimal seedy characters or potential situations for risk that was also well-lit. a lot of self-defense can simply be recognizing scenarios or areas that may present higher risks like that and avoiding them in the first place. the best way to defend yourself at an encounter at 3am at a shady gas station is to simply not get gas at 3am if you can help it at all. but even in those scenarios, you should always have a plan where a gun is the absolute last resort, and in my case, my escalation ladder started with attempting to avoid those scenarios whenever possible, selectively trying to manage risk by selecting environments/scenarios that present the lowest amount of risk, maintaining very good awareness in all directions, getting out of scenarios as effectively as possible, and then for confrontations, starting with clear verbal communication, and then if need be, escalating to solutions such as pepper spray, and then in the absolute worst case, needing to use a gun. i think 90% of people probably should really only need a good pair of shoes, physical fitness, and pepper spray, but I understand that not all people have circumstances where that would be sufficient and risk analysis is extremely personal to personal circumstances. you should also be very well versed in what will happen afterwards, how to talk to cops, how to talk to 911 after a self-defense encounter, a lot of this may depend on your state, but it is incredibly important to not put yourself in a precarous legal position in the aftermath, or potentially even a life-threatening one with responses. lots of people every year call the cops on someone after a self-defense encounter and get killed by cops after being confused with perpetrators, don't be that person. finally the last note about self-defense, personal circumstances involves financial consideration as well. don't bankrupt yourself buying guns, and also ensure that in the event any self-defense situation unfolds, that legal proceedings won't financially ruin you either. self-defense insurance is a must-have for anybody carrying a gun imo, i use ccw safe. there might be more that i'm forgetting but self-defense is a comprehensive and holistic consideration and gun people put way too much focus on simply selecting a model of firearm, although this can have differences such as a j-frame never being able to have the slide jammed and future shots being stopped by someone grabbing onto the slide, or clothing getting caught in a hammer and preventing a shot from happening, etc. but also clearly you should get a springfield hellcat :)