- better to play regularly for a short time (like 20 minutes a day, or even better: twice 20 minutes a day) than occasionally for hours on end.
- set yourself a goal and work towards it.
- beware: don't practice your own mistakes. Before you learn something, make sure you have it right.
- record yourself and try to find out what's right and what's wrong
- try to practice slowly, but regularly. Use a rhythm device.
- make sure you know the melody line (i.e. be able to sing it) before you start playing it.