I do 99% of my shopping at thrift stores. Most clothing stores are curated: a very small number of people are making choices about what clothes go into the store. If you know what fits your body, you like a store's style, and you really just want be sure that they'll have the thing you like in your size, then fine, go to a retail store. For all other situations, thrift stores are amazing.
Thrift stores have piles and piles of stuff made for all sorts of body shapes, all sorts of styles, etc. Where a big department store might have 20 different shirts in various sizes, a big thrift store will have 500 unique shirts. Where a department store or retail store will have a color palette of 5-10 colors, a thrift store will have all sorts of colors.
It took me a while to figure out how to make thrift shopping work. I'd grab a few things, furtively take a circuitous route to the change room, spend most of the time in the change room trying not to cry, and eventually settle on buying one or two feminine-looking things that I was able to get my body into.
Today, I do section shopping. I'll decide that I need more sleeveless tops, for example. I usually wear a medium or a large. I'll walk down the entire aisle, examining every small, medium, large, and extra-large. Every single one. If I absolutely love something, I'll grab it. If I'm not sure how something will look, I'll grab it. I keep going 'til I hit the store limit on the number of things that you can take into the change room, and try 'em on. My change room experience has changed thanks to HRT -- I'm not sure how this works for crossdressers -- where my criteria used to be "I got it on my body and nothing ripped," I now only keep things that I absolutely love and flatter my body. I'll repeat that until I've seen every single item in the aisle. Then, I browse the store to find things that match what I've found -- color, pattern, etc., to make sure that I'll have something to wear with them. This is a pretty tedious process, so I usually only do one section per shopping trip.
And if you get home and you don't like what you bought... it was only like $5 and it isn't the end of the world.