Here are my fool-proof 3 steps to getting a beginner up:
1) Try a little drill i do with beginners... Float on your back in the water, and practise sinking the board below you in the water. To do this, you will have to do 2 things. 1) knees up to your chest and bend them to try to kick yourself in the butt with the heal side edge of the board. 2) paddle your upper body forward with your hands. Do this a couple of times until you get the feeling of sinking the board under you.
2) Grab a handle and float in the water on your back with your arms straight and knees bent up to your chest. Have someone pull on the rope from the boat. when you feel pressure against the bottom of the board, try to sink the board below you by keeping your arms straight and trying to kick yourself in the butt with your heels.
3) try getting up behind the boat now. Do the exact same thing that you were doing for the last drill (ie. arms straight, knees bent up to your chest, when you feel pressure against the bottom of the board, try to kick yourself in the butt with your heels and sink the board below you). Have the boat driver accelerate fairly slowly and smoothly (with the right technique, you can get up almost at idle!)
Once you get the feeling of comming up out of the water, SLOWLY stand up and spin your front leg forward by pushing the handle down to your lead hip.
Two things to remember:
1)Arms straight (don't pull yourself up - you will fall backwards!).
2)Kick yourself in the butt (This actually does 2 things. First, it puts the board at the correct planing angle, so it will come up on top of the water instead of plowing. Secondly, it will force you to keep your knees bent until you are up on the water. Only once you are up on top of the water should you SLOWLY straighten your legs into your wakeboarding stance)
Hope that all makes sense!