Everyone wants to look fashionable, and clothing has been a way to do that since humans first discovered how to cover themselves in animal hides. From interesting cuts to interesting colors, there are nearly limitless possibilities when you go to build a wardrobe.
However, building a wardrobe can be expensive. Even if you want to build a wardrobe from things you find at the second hand clothing shop you're going to need to do a bit of work. It's not as easy as simply grabbing clothes that you think look interesting together and hoping for the best.
First and foremost, get a sense for what your best features actually are. Not everyone is shaped the same way, and not everyone has the same prominent features. Some female presenting people have great looking breasts, while others have shapely hips. Some male presenting people have broad, powerful shoulders, and others have a more slender body type.
This means you may not look good in some fashion styles. It's unfortunate when you want to put on a specific appearance, but not everyone is suited to every outfit. This doesn't mean that if you're fat you shouldn't wear a bikini. Only people who don't understand fashion think that.
Rather, it means that the clothing styles that best accentuate your most attractive features may not be the most popular fashion style of the moment.
That's alright, you don't need to worry about fitting current fashion trends precisely. The simple truth is that unless you have a specific reason to dress a certain way, such as for your job or a costume party, the important thing is to look nice. As long as your clothes look like you put thought into how they look together, you can generally get away with nearly any outfit.
So figure out what you look best in, and go with it. Don't try to fit an aesthetic that doesn't work for you. You'll look a lot better if you accept yourself for who you are.