I have used one Github account to push an android project to Github from Android Studio. Now I have created another account on Github and want to push my another android project
You need to first go to: Setting --> Version Control --> GitHub --> Change you username. (just like Nir Duan) said.
Then go to: VCS --> Checkout of Version Control --> Github
Log in with new credentials if asked, Change the Git URL and possibly parent directory, Click on clone, open in another window, wait for it to load. close the new window.
Next time you want to push you will see the new repository as part of the options at the top left on the "Push commit" pop-up