Keep trying on your clothes
I usually have one, or sometimes 2, try-on sessions yearly, usually when I cycle my winter sweaters into current clothing drawers, or pull out summer shorts, and get rid of a few things that way. But, I don't always have the time at the right time, or maybe am just not in a good decision/purge mood.
The other day I bought a new knit top that I thought fit really well. In several years past, I had bought t-shirts at different stores--not expensive--and have a bad (I think) tendency to buy several colors in each when they're inexpensive--an easy way to either save money, or waste it if upon reflection it's not your favorite shirt! So, I just decided to use my new shirt as a benchmark and tried on nearly all my good or semi-good T-shirts and even grunge shirts, and just said, I really only need the ones that fit like this or that--whether it's the changing styles, or low light in the store dressing room, or changes in my shape, I don't quite know, but you know when you just have that aha moment in your head, why am I wearing this (item of clothing), it is just not worth it and don't bother to buy anything else that looks like that! Similarly, I found a good pair of casual cropped pants that finally seemed to fit, and could say, egads, now I can get rid of 2 pairs that I bought several years ago out of desperation.
Remember the game Concentration? With cards, of course, but the TV show had the card squares turn and made a noise, click-click, and the host said something like, matching or not matching, similar but not matching--in much younger days, my girlfriends and I used to imitate both the motions and the words in other situations for fun.
So, newsflash, I am finding it is very helpful to drag out some of my older clothing at more frequent intervals, at the time I make a new purchase, and do this as I go along and go, hmm, outfit A or outfit B--are they both good, serve useful purposes, or does one now replace the other? And that can work better somehow because you've got in your mind then what your "standards" are. It has also given me more conviction to RETURN an item (this is especially important with mail-order purchases, because you are trying it on for the first time and it may not look anything like you expected, and it is so tempting not to go to the trouble of sending something back.) But, if you go click-click, item A or Item B, and the new item does nothing to upgrade or replace, then back it goes.