I would like some tips for some slapstick comedy especially prattfalls.

You might check this topic about falling:
how to fall (http://clown-forum.com/showthread.php?t=13955)

http://www.learnslapstick.com/

I would suggest learning from someone in your area in mime, dance, gymnastics, or martial arts to teach you how to fall. Also, please wear pads as much as possible. My 4x great grandfather Joey was heavily crippled by physical comedy. Davis Robinson of Bowdoin College wrote a book 'Physical Comedy Handbook', it's pretty good.