if u want to be admitted by top schools, u should do everything you can to study harder than your classmates. pay attention to social activities (eg, take a role in student government. be an active member of those competition and try ur best to win. if u do win the game, remember to keep those certificates as proof). the last thing, pay special attention to your big-named professors. try to get closer to them because their recommendations weigh so much. don't take toefl too early because it's valid only for 2 years (take it after grade 3) as gre, since it's good for 5 years, the earlier the better. ps, practice ur english skills as much as u can, especially listening&spoken. if u want to be a TA, or u'll would like to find a job after graduation, good communication'll increase the possibility, it's even more important than ur other academic skills all in all: prepare urself, as soon/much as possible. good luck | 
