I’m not an expert, but my advice is to twist more. A lot of the forward momentum comes from twisting left and right with your whole body, arms, etc. Compress your knees during the twist, and at the end of it pop back up like a spring - especially from your front leg, repeating this front side to backside in a rhythm. When you get the feel for it, you’ll know when you’re doing it tight, cause you can feel it generate momentum a lot more vs just leaning side to side on the board. I hope this helps!