I used to draw the same clothes (the first picture haha) on every character, until I learned from good criticisms that they're too similar. By trying out different stuff I learned how to make even the simplest things look interesting.
This is really sloppy but gives the general idea of using something simple and making it more interesting by ADDING STUFF! Hope you find some things you find useful from this. 8)
Also sorry the colors are so bad I just threw some random stuff on it haha.