If you go into your Gmail settings, scroll down and enable keyboard shortcuts, you can use the letter J to advance to the next email without moving your mouse across the screen to click a button, this feature and the fact that if you press the scroll button over a link, it opens a new tab without leaving the original tab, have trpled the speed at which I can earn credits. I also use quick tab change to click on the creidt images once i have about 30 tabs open.