First of all, you must have an Android Marketplace account. If you don’t have an account, you can simply create one on Google by clicking on the option of sign up.
Go to Android Market app from your phone’s main menu. Sign in to your Android Marketplace account. After signing in, type ‘Task Killer’ on the search bar which is appearing at the top of your screen and locate the app. Then, download the software application ‘Task Killer’ and install it.
After installing ‘Task Killer’, press and hold the application icon to place a shortcut of it at the desktop of your phone. Please note that you should create a shortcut of the app because you will be using it quite often and the shortcut will assist you to launch the application easily within no time.
After creating the shortcut at your desktop, launch the app by tapping on its icon. You will see all the applications which are running in the background and the foreground at your screen.
You can easily select the apps which you want to close by tapping ‘Kill App’ button which is visible on the screen. Eventually, all the applications will be closed in the background or the foreground which you have chosen to kill.
You may go to the Task Killer app on your Android phone at any time to close down the applications which are eating up your battery so as to save the power.