Focus on where you are going to put you hand on the rail - using what is normally your strongest.

The take-off is into the hand that is on the rail, as you can see. Leap up and over.

Keep the forward momentum by not leaning back too far. The temptation is to do so in order to get your other hand grabbing that rail quickly. Just chill, and keep the second grab delayed for as long as possible.

Your body knows where that rail is, so don't worry (if you were). Legs are being swung in an arc which becomes bigger and bigger as you become more practiced.

A dash like push-off gains distance, and this is why you should delay grabbing the rail. The longer you wait, the better a position you are for pushing away (by grabbing early, your shoulder joint isn't correctly aligned for a strong push).

Landing, and exit.

This move is similar to a lazy in the way that you swing your body up and over. However, it tends to be a little harder because you're striking the rail head-on, and so you must focus on clearing the rail before you grab behind you. Practice getting the push forward once you have your second hand on the rail in order to get some nice distance, possibly even precisions as you become better.