Step One: Rooting
Before you can start revving up your Android phone’s CPU, it needs to be rooted. Methods for rooting often vary slightly from model to model, but we’ve already written up a guide with a simple method that works for the majority of popular Android devices. If this method doesn’t apply to your device, the XDA Developers Forum is an excellent resource that is almost sure to have you covered.
In addition to being rooted, your device must also be using a custom recovery image, such as ClockworkMod. If it’s already rooted, there is a very good chance that you already have a custom recovery image installed; however, if you don’t, ROM Manager is a free app in the Google Play Store that can flash a custom recovery image for you.
It’s important that you know how to access your phone’s recovery mode. Again, this varies from model to model, but typically involves powering on your phone while holding down some combination of buttons. The ROM Manager app is also capable of rebooting you into recovery mode with the “Reboot into Recovery” option, should you prefer.