While there are a few methods, I use a very boring method. All my clothes are coordinated to match each other already, so it doesn't really matter what I wear. All dark shirts, and dark pants. And all my socks are black and the same brand, so it doesn't even matter which two socks I grab, they all work with each other. :) Although, for those that have different colours socks, sock locks are amazing!

I have a $1

My methods are boring too.
Sports clothes = pick any bra, any suitable style top, shorts, any two sports socks and then whatever kind of weather happens to be dictates the shoe choice.
Bikinis and swimwear = pick any too and any bottom :p
T-shirts used to be piled by theme and color. I'll need to go hru the shirts to get some more space as I'm sure there are several shirts I don't wear.
Dresses, cardigans and other longer items hang in the closet by style. I recognize things by texture and style.
Jeans also used to be nicely in a stack, and so were all long sleeved shirts.
Since pretty much everything (except sports clothes) is in dark colors, they'll match if the cut and textures aren't too weird a combo. Except of course for color combo rules, and those are also very culture specific. In Italy it's a mortal sin to wear blue and black on the same time. So sometimes to be on safer side of color combos I'll just use a color id app, or figure one bright colored item, or stick to boring colors... or on some days, use the colorblind card :)