You could practice a little in penny room of poker sites. This really won't cost you much(0.02/0.04) and once you beat them constantly, your friends should be a lot easier to beat.

People on these penny rooms play pretty much like your friends.
Against these guys:

#1 Be very tight pre flop, 20% hand. Don't call raises from BB/SB with trash. (i won't list the hands to play since someone else already done that very well).

#2 The 20% of the time, go ahead and raise it. Don't slowplay these guys.

#3 Don't bluff them of course....however what is exactly your definition of bluffing? continuation betting and trying to push someone off a hand is different. Even against fish, continuation is fine to me. However YOU CAN'T PUSH A FISH OFF HANDS.

#4 Are these guys readable or they simply randomely bet? you could try to read about tells, and learn their betting patterns.