You could use a "controlled" environment to practice on. find a good long staircase in town somewhere. The steps are all evenly spaced and won't roll out from under you like a loose stone or stick.
Lower your saddle. Approach it at a "jogging" pace. Fast enough that you wont feel every step all the way down, but not so fast that you air it out. Be light on your hands and use your limbs to absorb the shock. When you get to the bottom, don't lean on your arms, rather pull back/up so your front wheel isn't jammed into the landing.
Do it several times. Then go find a small ledge or picnic table to practice riding off of.
If you practice on obstacles larger than your trail features, then your trail features will seem easier.
I've got mixed feelings re this thread. Two yrs ago I bought my XC 29r off my mechanic just for winter commuting but (subconciously) must've wanted to try the trails. Now I can't get enough of this. The challenge is, at 40, its more work to unlearn lots of bad habits: I'm forever grabbing the rear brake for example, can't navigate mud very well etc. Manualing is just not happening for me, nor is bunny-hopping...
So, 1. if you spot me out there on the trail, going ugly over obstacles, withhold judgement...or, whatever, judge away.
& 2. Please keep the thread alive b/c this is like the cliff notes for trail riding. Finally 3. the excerpt above is excellent.