1. Use A Mouse With Programmable Buttons The first thing that you need, is a mouse that has a bunch of buttons on it. There's no need to go crazy, but I find that 6-8 buttons are perfect. Before you start imagining something strange, these buttons are usually already programmed with tasks, such as scroll down one page, zoom, etc. You can configure these buttons to do quite a few things. I use a select all command (CTRL+A) on the scroll wheel button, copy (CTRL+C), delete, paste (CTRL+V), and close (ALT+F4). These are commands that I use all of the time. Programming them onto these mouse buttons makes a big difference and it's a lot faster than punching those keys manually.
2. Mouse Movement I find that I like having fast acceleration on my mouse. The main reason is that it takes less movement to move my mouse around on my monitor. I don't like it lightning fast, but pretty fast. This will cut down on large movements that you have to do with your wrists. Sometimes, this makes the mouse cursor hard to find, which is why I enable larger mouse trails and finding the mouse when I press the control key. 3. Scroll Wheel Speed Scrolling down page after page is convenient, but not in all situations. Sometimes, you just want to scroll down bit by bit. I find that setting the scroll speed to something like 6 lines at a time is best. 4. Have A Backup Pointing Solution Modern mice have integrated batteries. If you forget to charge your mouse at some point in time, you'll end up running out of juice. It's happened to me and if you don't have a backup solution in place, you'll have to do without a mouse for a while, by either using a trackpad of some kind, or just using your keyboard. I have a cheaper Logitech mouse around that functions on AA batteries. It's perfect when my main mouse is being charged. 5. Don't Drop Your Mouse My main Logitech mouse is currently on the fritz because my cat tends to drop it from time to time, and yes, I get the irony that my cat likes going after computer mice! Luckily, it's not a recent addition so I don't mind it all that much. However, I've ruined more than one mouse by dropping it, so best be careful. [Top photo by Dan's Tech Reviews, mice photos via Wikipedia: 1, 2, 3]