There are some apps that go unappreciated because they work so efficiently and quietly in the background. It’s only when I work on another Mac without BetterTouchTool installed that I realize how much I rely on it every day.
Admittedly, at first glance the UI isn’t pretty. Delve into the various options, though, and you soon realize that with just a trackpad, and without having to use keyboard shortcuts, you have the power to do anything.
For example, let’s say you often switch between tabs in your browser, perhaps several dozen times a day. Traditionally, the only ways to manipulate tabs is to drag your mouse all the way to the top of the toolbar or use esoteric keyboard shortcuts like
⌘⇧] to switch to an adjacent tab.
In the example below, I use BetterTouchTool to convert three-finger swipes on a trackpad to swipes from tab-to-tab—a natural-feeling motion for switching between objects.
Let’s break this down:
- I make sure I’ve selected the app (Safari) I want to affect, in the left-hand pane. Then I click Add New Gesture.
- Under Touchpad Gesture, select, well, your gesture of choice. (Note the helpful animation to the left, demonstrating the gesture you selected.)
- To the right, you have a couple of options: 1) Use a predefined system action, like showing the Desktop, or 2) use a custom keyboard shortcut.
- In this case, I found out that
⌘⇧]corresponds to moving to the tab on the right while
⌘⇧[corresponds to moving to the tab on the left. 
You can apply this logic to all kinds of different actions, like creating and closing new windows with just the trackpad, or opening a Finder window by triple-finger clicking on the Magic Mouse or trackpad. These may seem like small improvements, but altogether, these shortcuts save a sizeable amount of time, and end up feeling like a natural extension of yourself.
You may have to experiment with which keyboard shortcut corresponds to which gesture. With Mac OS X 10.7 Lion, Apple switched to enabling “natural” scrolling by default. So when you swipe up on the trackpad, you “push” the page down. It is difficult to describe, but at first it feels unnatural. Until you just get used to it. ↩