I've been MTBing since i was 10, my mates and I would spend evenings either on dartmoor or in the school grounds learning how to jump/endo/bunnyhop/sidehop/backhop, aven spent one silly summer learning how to wheelie without a front wheel! I am 100% certain this is why I'm happy hopping along on trails now.
That said - I am scared sh*tless of big drops and rarely do manmade jumps.
If you want to improve your bunnyhopping skills - go to Princetown and ride the smooth, but drain-ridden track toward the widowmaker over and over again. You'll either learn or destroy your wheels in the massive gutters/bridges you have to ride at speed! Once you can do it, all of them are clearable and if you hit them heading toward princetown, some of the best fun you can imagine!