How hard you cut when you first start the run almost doesn't matter. What really matters is how hard you are cutting when you ride up the wake.
Many people make the mistake of cutting hard at the start, and then flattening the board out as they hit the wake. This does two things;
1) it turns you in the direction of the boat, which causes you to get slack in the line and really cuts your speed across the wake.
2) By not edging up the wake you lose the upward pull that the tower can give you, and you don't get the height.
Instead of trying to cut harder, do a "progressive" cut. Start off slower, but edge harder and harder as you approach the wake and hold it all the way up the wake.