To save battery:

I usually just set the Nexus 7 to airplane mode when I don't need to be connected.

I also use one of the toggle apps (right now using power toggles) for a home page widget to toggle wifi, gps etc. Since it's easy to toggle I don't get lazy about it and everything stays off until I want it.

Also, everything that automatically updates and syncs is set to do that manually, where that is an option. e.g. everything under accounts, email, weather app etc.

Having the screen all the way bright will also draw the battery more. I keep mine about halfway since "auto" is usually too dim for me.

The case for my Nexus has a little magnet which shuts it down when I close the case. I figure that saves a little on the battery since it never has to wait on the timeout to shut the screen down.