Transitions : This video goes over the key skills for dismounting and remounting your CX bike. Transitions are key in CX racing and if done correctly they can save a lot of energy. Oh ya... just ignore the part about crossing your leg through.
Cornering: While this video doesn't start with the quality music of the first video (Transitions), it provides a clear overview of cornering. It also provides some tricks to use when passing or to prevent passing on corners, so watch until the end.
Sand: While we don't get a lot of sand pits in SoCal, it is always good to know what to do when one comes upon you. This goes with any really soft dirt or transition from hardpack to softer terrain.