I usually test like five or so out of however many I get, a day, and remember the ones that I like on me.
Then after I've tested them all in mass quantities, I start wearing 2-3 at a time, getting a feel for what my favorites are.
I then compare favorites like a tennis tournament would go - I forget what it's called, MLB or round robin or something, I used to play smash competitively - and try and pick out one of a type I am looking for to add to my collection. Then I'll wear it in the day that I have during the weather I expect to be using it most. And maybe I'll compare scents in such circumstances. Eventually I find a winner among types, and there may be more than one type I look for at a time.