I had a similar problem because last year was my first year in the park. Make sure the rail is a flat rail not a rail with an angle to it. You need a 180 degree (flat) rail. The easiest way for me has been said above but I can reword it incase you did not understad it up there.
1) Firm pop - I have the rail in-between my legs when I pop.
2) Don't over think it. Picture yourself finishing the rail. If you overthink it or overstress and think about every little movement you are going to fail. That said don't just wing it. Go thought what you are going to do mentally then do it.
3) Watch the landing/end.
4) Land with style and go bang bang at the camera and feel amazing,].