This achievement might sound difficult, but it is actually very easy.
To make a video worth 20,000, simply record yourself making really good combos. Press START, VIDEO EDITOR, RECORD NEW CLIP to start recording. Each video should be around 20-50 seconds. You can make multiple videos, but you only need around 3-4 to have enough points. Once you're done with your videos, go back to video editor and hit Create New Edit. Then on the first tab, Edit Clip, insert the clips you want to use. Once your done, press B and scroll to the right to the Submit tab, and choose Sumbit Your Edit To Volcom. If your clips were good enough, the achievement will unlock once you submit it to volcom.
*The clips that you put in your video must be in the same area/city.
*Using cheats (perfect grind, no bail, etc) makes this achievement much easier. (Yes, using cheats DOES NOT disable achievements in this game).