SketchFactor has posted a good write up over at
Bungie.net in which he goes over several maps that he himself has made using the Forge, as well as gives tips for would be Forgers.
- Start with a central idea / focus / hook
- Placing walls sucks.
- Co-Op Forging isn't for everyone.
- Build a language for your map.
- Set Pieces Are Neat
- You can never have too many spawn points.
- Practice (and Patience) makes Perfect
Click the link above to check out his creations, download them if you want to, and also get more details on the tips.