Maybe you should try hills with less incline to train yourself.
I'm not a great climber and this is what I learned.
Get into the small front gear before the hill approaches.
Lockout my shock/fork if necessary. Or adjust travel to lowest setting if available.
Shift the rear ring to a gear that I can feel slight tension in my pedaling.
Sit on the nose of my saddle.
Grip the bar with my thumbs on top and tuck my elbows in towards my waist.
Lean forward.
Pedal.
While climbing, shift the rear as necessary but never too much because you'll make too much torque and either slip the rear tire or wheelie the front.
That's all I can add.

BTW, using momentum is the worst thing if you can't make the climb normally because you'll be in too small of a rear ring while approaching the hill, to get as much speed as possible, so when you lose that momentum, which eventually will happen, you're in the wrong gear and often come to a complete stop.