ok i have been jumping for almost 2 years. the best way I have found is when starting out try different gears in jumping. As a beginner i suggest 2nd...depending on what size your bike is. Next, as u go up the jump keep giving throttle and as u hit the hill/ramp push down on the bike...this is called preloading the suspension which will help u get the bike in the air. As u reach the top of the jump when u are about to go airborne it is best to not lean to one side, leaning forward creates a spring action that will cause the rear of the bike to shoot up, also do not lean too far backward or the front end of the bike will keep rising and will make the landing hard on your back...trust me! If u do it right u will go airbone! Good luck! and have fun!
P.S. Keep your eyes on where u are landing!