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.