Tab browsing - Simple, yet so useful
Ok, so I got a little bored...
I was trying to experiment with my firefox browser... I usually switch through tabs by doing ctrl + tab for left to right tab browsing. But I wanted to to it backwards... I just experimented with the keys and got ctrl + shift + tab for reverse tab browsing. You could also apply the same principle when browsing through forms(if you're feeling lazy to use the mouse) by doing tab for forward(left to right) and shift + tab for reverse.
Of course this is for Windows. It's up to you to figure that out in your Mac!