The first thing would be to look at how you draw, and if it is good. It could be people pay more attention to your sister, since her drawings are better than yours. You can also look at the kind of anime you are drawing; you should draw the most popular, and interesting ones. In this way, people will be more attracted to your work. As long as you get a drawing that is popular, interesting and well crafted, you should get as much attention, as your sister.
Well if your sister is older its natural that shed draw better than you because she has further experience. If your sister is younger a way to try and become better is to simply change your style. Not like change from anime to cartoon but change the way you draw anime. Theres tons of eyes you could do so if this type of anime doesnt make you feel successful then drawing it wont make you any better.