Here are a few tips for World of Warcraft that I have found to be helpful and yet not so obvious:
1. “Num Lock” triggers autorun.
2. Quick looting: shift-right click to autoloot everything from a corpse.
3. Quick mining/harvesting: shift-right click to mine/harvest a node AND auto-loot it.
4. More info: hitting the “V” key will bring up names and health bars above all NPCs and mobs.
5. Bag management: shift-B opens up all bags for easy access.
6. Taking screenshots: alt-Z switches off the UI to make them look nice.
7. Managing stacks: shift-left click on a stack, enter the number, click on an open spot in your bag.
8. Check out the alternative interfaces available such as Cosmos and CTMod.
Oh, and let these take your breath away for a small moment in time.