theres MANY ways to do it.
1. top it, in other words, cut the tiny growth tip at the top of the plant, but this causes alot of stress on the plant, which may turn it to a male.
2. turn the lights to 12/12 as soon as the seedling pops through the ground, but depending on strain it could grow much taller than 10in.
3. LST (Low Stress Training) you tie the top of the plant almost to the soil and keep doing that....
any way you choose, youve pretty much have no choice but to flower as ealy as possible.
check the GROWFAQ. everything you need is in there
have fun