Of those listed, I found the following most helpful to me:
I have mine set for 1 minute.
Make Sure the Screen Locks QuicklyEven if you’ve adjusted the screen brightness, there’s still no substitute for having it turn off quickly when you’re not using it. Head into General -> Auto-Lock to set the screen lock to happen as quickly as your device will let you. This makes a big difference if you are always picking up your phone and putting it back into your pocket without turning the display off.
My grandson recently loaded Angry Birds on my phone but I much prefer iFishing, Spear Fishing 3D, Sims 3 World Adventure or Sudoku and I hate to be interrupted if I have a fish on!!
Use Airplane Mode When You Don’t Need Internet (iPad/iPhone)If you’re busy spending the next 8 hours playing Angry Birds, there might not be a good reason to have internet access, so you can consider using Airplane Mode, which turns off both Wi-Fi and the regular wireless radio. Of course, this will prevent phone calls if you’re on an iPhone—but if you’re busy with Angry Birds you probably don’t want the interruption anyway.
I actually can't get a cell signal when I'm at home anyway so I always have my Wifi network configured to ON.
Use Wi-Fi Instead of 3G if PossibleAccording to Apple, the iPad will get 10 hours of battery life under regular use with Wi-Fi enabled, but will only get 9 hours using 3G—the iPhone gets 6 for 3G and 10 for Wi-Fi. Of course, if you’re heavily using the Wi-Fi, you’ll still be draining the battery—the point is under similar workloads, Wi-Fi is better than 3G for battery life.
Now that I'm retired, I don't have to worry about someone other than me updating my calendar and I seldom use my iPhone to check mail. Since I no longer have to worry about malfunctioning servers or frantic grant researchers who can't perform some technology function and are facing a grant submission deadline, I can usually wait until I'm in front of my regular computer to respond to email. So I turned off the constant checking and will just manually enable it if I need to take a peek.
Reduce or Eliminate Mail & Calendar CheckingIf you’ve got a bunch of email, calendar, or contact accounts configured, and they are all being checked and downloading email on a regular basis, you’ll be draining the battery an awful lot faster than you need to.
Head into Settings -> Mail, Contacts, Calendars -> Fetch New Data and change the setting to the least frequent check possible. If you don’t use it often, you can just turn Push off entirely and then manually check when you need to.
Since I never treat talking on the phone as a priority I have never seen a reason to buy a headset so this one was a no brainer for me.
Disable Bluetooth If You Don’t Need ItIf you don’t use a Bluetooth headset or keyboard, you should keep the Bluetooth radio disabled to save some extra battery life. Head into Settings -> General -> Bluetooth to flip it on or off.
Probably the most important advice was at the end of the article.
Charge and Discharge Your Battery RegularlyYour iDevice needs to be fully discharged and recharged at least once a month to operate at maximum efficiency and keep the battery from dying. You’ll also want to make sure that you don’t store the device with a dead battery, as that can also cause the battery to lose charge capability—when your battery dies, make sure to recharge it quickly.
This one is hard for me since I seldom run my phone's battery down. This also probably applies to laptops and serves as a good reminder for me since my netbook has only been recharged a couple of times since I returned from Rome in March of 2009. I'll obviously have to be more dilligent!