Rev to 4k rpm, lean forward on the tank (I actually lay on the tank). When the SECOND YELLOW light comes on let the clutch out untill it starts to enguage, then roll into the gas. It is important not to get the bike revving too high at this point. You want to get the bike rolling with the clutch and get it accelerating with the gas. It all happens pretty fast, and takes ALOT of pratice to do well.
The most important number on your timeslip will be your 60ft time. That tells you how well you got off of the line. When you are doing it right you will be pulling 1.8something 60fts. 2.0 and up means you are either using to much RPM on the line and spending too much time on the clutch because of it, or you are launching to soft.