[Samsung Galaxy Nexus] Amphibliam:
Screen Brightness

For 99% of users, the display is the #1 consumer of battery, which makes sense because you have a giant 4.65 inch 720p display that needs lots of power to run. The lower you set your brightness, the more battery you save. For a person like me, 50% brightness is usually the highest I use. Colors look clear, the screen is plenty bright to read, and yet it's not too high. If you want to save battery however, turn down the brightness to around 30%. If you're really in a pinch and need to save some juice, you can even turn it down all the way to 0%, but I would recommend keeping it around the 30-35% mark for general usage. In my experience, standard auto brightness doesn't work too well for me. It's slow to respond and either cranks the brightness way up or way down inappropriately. However, some ROMs like CM10 allow you to modify the backlight settings, which works quite well.

Maps/Latitude

This tip is a little more straightforward. If you use Google Now, you are using Maps location services which drain battery. It's always looking for your location to give you the latest weather, let you know about the cool sushi restaurant down the street, and other neat stuff. However, it needs to know where you are, so it's constantly polling the network for location data. So, shut off Google Now completely, or if you're like me and love it, just shut off the parts of it that you don't need, like Places and Traffic. I saved the big one for last. Latitude. The silent battery killer. If you're like me and you never use Latitude ever, guess what, it's probably still using your battery, so you need to shut it off. Simply open your Maps app, hit menu, then settings, then location settings, then disable location reporting and location history. Your battery drain should decrease significantly. I check this often because it seems to reenable on its own sometimes. Yikes.

Radios

WiFi is pretty fast at your house. Way better than 1 Bar of 3G. But when you leave, you leave the WiFi on, thinking it's no big deal. However, WiFi is one of the biggest battery killers, along with the other radios. So remember, just shut stuff off when you aren't using it. No navigation today? GPS goes off. Not using your headset? No bluetooth. Haven't invested in those fancy NFC tags? Shut that off, too. A big one is LTE. If you live in a 3G only area, what good is it to keep LTE on? It's just draining your battery. Turning Data off can save you money and battery. If you aren't one of the lucky ones still on an unlimited data plan, shutting data off will stop apps from using data in the background, and it'll also save a bunch of battery. However, you won't know when fnartsy123 liked your Instagram photo.

Apps

There are some apps that constantly use system resources and keep your device awake, even when you aren't using it. A major offender is Facebook. While a big update is rumored, the apps frankly sucks right now. It's slow and it drains your battery. Stick to the mobile website, as honestly, it works better now. That's the main one, but there are plenty of other. To identify them, I recommend an awesome app like Better Battery Stats or Appsucker from Google Play. They'll tell you what app is stealing your juice, and you know to remove it.

Auto Sync

One of the main reasons to own a smartphone is to stay connected, and I don't want to change that. I would recommend you shut off syncing for services and apps that you don't use. Check your Google account settings. You don't need or want all of your selfies to end up on Google+? Shut off instant upload. If you use Chrome instead of the AOSP browser, shut off sync for that. Go through and make sure you only are syncing what you actually use. Also, check your apps. Do you need to know when you have a new tweet? If so, leave it on. If not, shut it off. Furthermore, if your battery is in the red, shut off autosync altogether to save some serious juice.