Best things to do are : eat healthy, sleep a lot, and not to much stress... Of course easier to say than to do. But it won't make you a lot taller, I mean it's genetic! Just know you're not alone, I'm also little and I'm 16.
It's all relative. I'm an adult (physically at least) and 188 cm and I'm one of the shortest guys in my family and I have always wanted to be taller. Adult height is a matter of genetics and that, pretty much, is that.