I feel you! My tummy has always been my issue with my body, but it's got SO much better in the past years! I find two things that have helped me most - looking for styles and colours that I know I like (getting much help from here!) and changing my thoughts.
Learning more and more about what styles and colours that I like and that I think work for me means that I focus less on those things that doesn't work as well - meaning that I don't have to be negative and jealous of others who can wear those things, instead I focus on "my" things when I go shopping!
But a big part (maybe the biggest) is your thoughts. I've actively worked with that, noticing what I'm saying to myself and changing that. NOT forbidding any thoughts - thoughts and feelings will be there whether you like it or not, but when I feel negative I try to reason with myself. "Ok, this is how I feel now, and I don't have to love every part of myself. But this is how I do look, and my body functions, which is most important. My tummy is there and won't go away, that's that." Something like that! I've also worked on actively thinking positive things about my body, specifically my tummy, when looking in the mirror. Even if I don't feel positive I can think "Hi there cozy tummy, you're MY tummy!"
Haha, I might sound crazy now, and I think everyone has to find what works for them, but I know that these two things have helped me feel much better about my body, and not letting the negative thoughts take over when they come.
Hugs!