I've posted my final article in a series of tips for playing LoL. This one covers what you should learn/know for playing at Level 30:

http://nightmaremode.net/2012/08/lol...rt-tips-21755/

Tips covered here:
1. How to play a support
2. Two wards will stop most ganks.
3. Recon Escalation: Green wards, purple wards, and Oracle's.
4. In Ranked & Draft, your order determines your role.
5. Starve the enemy: zone them out.
6. Know when to leave your lane.
7. Check the scoreboard regularly.
8. Invade their jungle, but move fast.
9. Counter jungle.
10. Taking the Baron.