Oh no no no....
where do I start. Android 2.2 and above has an internal auto task manager, a very well design one I must say, which kills tasks as resources are needed, just because an app is "running" doesn't necessarily mean it's really running processes and consuming battery in fact almost all app "running" in the background are just loaded in memory not using battery. So killing your apps every 30 minute will result in more battery consumption than just letting them sit on the memory. Why is this you might ask, well let me explain when you open an app your phone has to do a lot of processes to start that app consuming battery, but if that app is already loaded in the internal memory than your phone saves all those processes every time you open that app.
If you're serious about saving battery first you have to understand where your battery is going.
I recommend you use SystemPanel. Thisapp will monitor every process from every app. If you see an app that is excessive try to find a replacement.
Now go to your home screen and long press on a empty spot and select Shortcut, Settings, Battery Use. Here you will see what is using your battery. In my experience this is what I have observe. Screen uses 50 to 75 percent depending how long your screen is on. Antennas (2G, 3G, wifi, Bluetooth) uses about 10 to 20 percent of the battery. and processes use about 10 to 15 percent isbattery use.
OK so lowering your screen brightness will have the biggest impact. Second keeping an eye on your Bluetooth and WiFi will help too.
And my last tip is probably the most important, draining ALL the battery and charging it until it reaches 100% it will increase your battery life up to 40% more.
This is what I do I bought an extra
battery and a battery charger like this ones. All I do is cycle through them.