Oh, this is a problemo for me.
I agreethat sizing issues and style issues are different. I really like to try multiple sizes at once. You'd think I'd have the "internal compass" for what size, but style of fit is so...well... fluid now that I find myself all over the map as to how I want a particular garment to fit--tops mostly. Bottoms have different fits as well but usually they sort themselves out as right or wrong, more so than tops.
What's difficult is to identify what brand or maker's garment of what type I should get, and how much effort to spend looking, how many to try. As in, here's a nice chunky knit pullover for skirts, but will the next one I find be better? This isn't as hard if I'm trying to decide between 2 pairs of gray pants by the same maker --I'm okay with ordering both--but if you start thinking about all the retail options and how not everyone brings out all seasonal items at the same time--it gets mind-boggling. Usually you can't accumulate 10 sweaters,, tags still on, over 3 months and then decide. And then there'd still be next month's.
I recently read the WSJ article on how people make decisions--maximizers or satisficers--a spinoff of Barry Schwartz. Not sure it helped me.
What has helped me is all of the things that may have helped focus my ideas about what fits, what flatters, what silhouettes and colors I want. That makes it more likely that I will "recognize" an item by itself and not just by comparison.
Then of course you have to also be a grown-up and dance with the one you bought. New chance next year, or whatever.
Along with that, I have found it helpful to try on a lot of different things when I'm in a store. This has helped also with honing in on a target look. This has helped me NOT order some things online, or vice versa. This has been especially helpful for "trends' that others are wearing. I can test them out in stores. For example, a lot of tops that work great for "apples" are not good for me. I got a silky-front sweatshirt this year and while I liked it some, I began to see it just wasn't my direction. Same with a lot of banded bottom tops and cardigans. So I began to try on a larger range of items in-store just for retail research to keep hitting myself over the head with, "remember, you don't like how that looks on you" and not get sucked in by the lovely colors and prints.
From all of that I think I am trying to develop a flexible list-if I'm focused on "must have," I am likely to settle. If I identify 2-3 options in various categories, I can try to stick to PPP and happiness factor for the item.