A nice distillation of the Common Base Locations thread could be useful, with the personal building lessons excised. Also, what noobs could really use is a brief overview of the common strategies for the default maps. One of the wikis gives some map hints, but a real review of the default maps and the basic team mission for each would be something that would help players to contribute more fully to the game. Almost a Prima Guide type of a walkthrough of each map, with the common room names, basic strategies, and a well-built base for each Stage illustrated fully.
For example, on ATCS you can pretty much stay in your base. On Karith, Aliens generally move into the lift room, while Humans move under the walkway (at the end away from the stairs). While some of this is explained in one or two of the wikis, they are very brief. A deeper, fuller explanation would be very helpful for newer players. While no two games of Tremulous are exactly the same, experienced players know the usual moves. Like guarding the vent into the lift room on Karith. Or getting that lucispammer by going out the front door, wallwalking up to the outside opening of the vent, and biting him right on the ass.
Some things, to paraphrase Hemingway, can only be taught by experience (like sex or bullfighting). While this is partly true for Tremulous, a little mission briefing sure wouldn't hurt.
In other words, if you're gonna do a wiki, please try to do something that hasn't already been done. Or improve an existing one. What Caveman said.