Any Advice on Teaching Large Classes?

Most of the classes I have taught in the past were fairly small. Usually they averaged between 15 and 30 students. The largest class I taught was under 50 students. Next semester I have two classes to teach. One of them will be significantly larger than what I have taught in the past. Does anybody have any advice on teaching large classes? Are there any specific techniques that are better geared towards large classes? Any advice anybody could give me on effectively teaching a large class would be greatly appreciated.