The brilliant DivisionByZero from the City of Arabel NWN RP-PW has written some EXCELLENT guides to roleplaying. Both people who have never roleplayed before and old timers who've been at it for years can use these guides.
The Art of Roleplaying
Mostly for newbies, this guide contains:
- Roleplaying and In Character Defined
- Rolling with the Punches
- Balancing Realism and Fun
- What is OOC Consideration, really?
- Retiring a Character
- Respectful Disagreement