What should l do and practice to get better at killers and rollers?
I've been playing for a week and not to brag, but i'm pretty good for that time range. At least, everyone i've played said i'm good. for someone whos played a week. l just need more practice on killers. Any advice?

exercise your arms so you can hit the ball harder

http://en.wikipedia.org/wiki/American_handball#Terms.2C_Techniques_and_Tactics

go here!.theres a list of good techniques!..

and the guy on the bottom of me is WRONG!

the guy above me is wrong. it doesnt matter about strength at all in kill shots. l play handball everyday with me and my friends. try hitting it at the corners so that it lands near or on the line and then they have no chance of hitting it...also never hit kill shots with the palm of your hand. hit it with your lower fingers.. it will give you better accuracy and better spin.. hope l helped :)

tuna is right it is best not to hit with your palms. when you hit it with your lower fingers the balls go faster and have better spin making it harder to get. YOu will be good when you perfect your killers. best answer please.

Hitting killers just come with experience, just keep practicing and eventually you will know how to hit one.
l dunno if it helps but sometimes l warm up by throwing and hitting the ball against the wall and trying to go for killers.