Crankflip help!

Ahhhhh, I cant get a crankflip for my life! Anyone out there got any good tips? When ever i try my foot like sticks to the pedal and throws the out ouf of my hand and out forward aobut 10ft, and the cranks dont even turn 180º! grrr, im so mad, and i was stupid and learned crank spins on my non hopping crank position, so i am forced to learn crankflips backwards.