Uhhh I pick clothes I like. the most recent maru sketch i got was just one of Momo Ayase's outfits in Dandadan. For her canon outfit, I'll be real I kinda improvised. I wanted the like. silhouette of a western-style duster but with her abs out, so it's got the cropped vest & torn shirt, and then there's supposed to be this like. Waist-cloak thingy. and for the beach Colt fit I remembered seeing a cute checkered bikini w/ flames on tumblr, like, years ago, so I went looking for it again and am very surprised I found it.
As for style consultancy, I don't think I can do what I do for myself for other people, sadly. Sorry. You gotta know what you want and seek it out. And if you can't find it, make it.