Gray Vert

The key is landing at the very top of the ramps to retain speed. You should be going from one wall to the other as you are in the air (without hitting the walls). If you gain horizontal speed while in the air, you can convert that speed into vertical speed the next time you launch off. While you are in the air, you might want to release forward at some point to position your landing using the left/right strafe keys. Launch off the ramps straight-on, not at an angle.