Google's mail service, better known as Gmail, has a nice feature called keyboard shortcuts. This way, you can simply use your keyboard to navigate fast trough your Gmail account. I created this cheat sheet with they keyboard shortcuts from Gmail and what they do. Print it and put it next to your PC, you'll never forget an shortcut again.

For those people that don't have the keyboard shortcuts enabled (yet), go to the Settings page of Gmail and turn them on there.