That is, when you go up, turn around and ride back down. You have to turn at your highest point, where you're hanging in the air. Dont jump up, like most bladers do, but just push harder if you want to go up. By now, you must have realized that its not only hard pushing that takes you higher. Its also timing.
Timing is essential while riding vert.
So, as soon as you're going down again, start pushing. You will go up higher at the other end. Its a feeling. When you turn, it has to go fluendly. See it like walking.