If your valves are set to tight (don't have enough clearance), it will cause trouble hot starting.
As far as technique, use the kicker to slowly bring the piston to the top of the compression stroke. You will feel it get harder and harder to move. Just after TDC, the piston will get easier to move with the kicker. Stop slowly moving the kicker just as the piston passes TDC. Now raise the kicker to the top and kick as hard as you can. By getting the piston just past the compression stroke before you kick for real, the piston has a chance to build up more speed before the next compression stroke. Also, some bikes are very picky about throttle position - most don't want any throttle unless they are flooded. If flooded, kick with it all the way open until it starts (don't open and close it).