I'd basically go with alan plotz' tips. Let's sum it up and add maybe one or the other thing: It's important to understand two things: PROGRESSIVE EDGING and taking off correctly by STANDING TALL AT THE TOP OF THE WAKE.
You can practice both independently, but I would not recommend it. Try to make your cut and your take off one fluid motion. For clearing both wakes you should not need to cut out more than 15 feet, do not cut out all the way (in fact it's even possible to clear both wakes from just 3 or four feet outside the wake).
So cut out, flatten off and let your board coast for like two seconds. Be patient and wait for the boat starting to slightly pull you back towards the wake. Now bend both knees slightly, lock the handle at your waist, a little toward your lead hip, and set a progressive edge.
This means: slightly lean back against the line to start your cut. As you're approaching the wake, increase your line tension by leaning back more and more - but not too hard - you have to stay in control and still be able to keep the handle in. Now really concentrate on staying on edge as you cut through the trough of the wake. Cut all the way through the wake. This is when you want to have the most line tension.
Then take off from the very top of the wake by extending both legs. You really want to push against the wake with both legs equally and stand as tall as you can while keeping the handle in.
This will give you some great pop and you will stay in control for the landing, so have no fear from the energy you build up and release by using this technique.
All this sounds way more difficult than it is, but nevertheless it takes some practice --- but I promise, it will be worth it!!! It's also the very key to more advanced tricks like back rolls etc.
So keep going at it and have some fun