It's always great to learn from the experts, and FPS Magazine has a great article online on How to Mount an Airsoft Ambush. The article talks about about how to organize your Airsoft team for an ambush, scouting locations for a perfect ambush, and the different types of ambushes. It's a great read, and will help your team get ready for your Airsoft skirmishes.
Don't forget that FPS Magazine is the only Airsoft dedicated magazine published in the US. Give 'em your support.