The "ignore accidental trackpad input" and "ignore trackpad while typing" don't seem to be completely effective.
I've had issues in the past with having the mouse jump around, and it was almost always attributed to my brushing the trackpad with the inside heel of one of my hands. Some trackpads are more sensitive than others too, and can actually track your hand movements when they're just above the trackpad, not touching it. This seems to be more of a problem when the humidity or temperature are higher. My wallstreet's trackpad was sensitive enough that I could operate it through a *telephone book*. (I kid you not... freaked us out when we tested it... paper, magazine, cardboard, the back of a clipboard, and finally a 1" telephone book) It's not tracking on pressure as the clipboard back test verified - I'm fairly sure it's tracking body capacitance.
Anyway, Besides changing your hand position on the keyboard, I can't really suggest any good solutions besides turning off the trackpad completely and using an external mouse. There are some nice mini bluetooth mice around, if your computer has built-in BT.
- I work for the Department of Redundancy Department