Does anybody have any particular techniques they find helpful for trills? I just finished reading through La Campanella; if it taught me one thing, it's that my trills need work.
Find a piece that has lots of trills it it, then isolate those parts. One example is Mussorgsky's Pictures at the Exhibition: the chirping of Chicks in their shells (or whatever the title of that scene is.) The worst possible trill fingering has to be the 4-5 fingers like in Beethoven's Op.111.
Most of Beethoven's later compositions require superb trill technique. Nothing an amateur can successfully execute, especially because the hand that trills must also play the melody line...Op.53 requires trill for 1-2 fingers, melody played with 5-4-3 fingers.Op.109, same for above but a bit easier to do as your hand isn't as stretched.Op.111 requres trill for 4-5 fingers, melody with thumb.