Do you mean learning lines?? I've found that when crunched for time, the best way to learn lines is repetition. Often, when I was short on time, I could never find someone to help me run lines... sooo... I bought one of those cheap tape recorder things and recorded the cues. That way, you can run lines with yourself. It sounds crazy, but it works.
Run, run, run your lines! That's the best way!