Feel free to add your own if you'd like, but here is what I've found to help out with battery life.
Mind you, I'm a battery saving junky since I had my Droid X and the batt wouldn't even last me until 4PM after being off the charger at 730AM (9.5hrs) even in little-to-medium use!
Apps:
4G Toggle - This sits on your homescreen and allows you to quickly toggle between 3G and 4G without going through settings. It's handy tool when you're not in a 3G area, or just don't want to use 4G.
Data Enabler - Another homescreen widget that allows you to shut off data when you're in a bad area, not using it, or using WiFi. It's a one-click option that shuts off 1X, 3G, and 4G.
SmartActions - Learn to love this app. You can customize this to just about anything you do. Bluetooth in the car while driving? It can disable wifi, set screen to auto-brightness, open up your car dock, and change your ringtone if you want, and more.
Here's what I have set as an example:
When I walk into work:
Wi-Fi connects to my network
Data Connection off
Bluetooth off
GPS off
brightness set to min
Ringer to Vibrate
With the combo of these three apps on the Maxx with medium use on average, and leaving it overnight to sleep (with a sleep mode in SmartActions), I'm getting on average 1 day and 12 hours on battery according to my widget.
Feel free to add your own tips/tricks if you'd like! This is an open thread for everyone, so share!