Don't try to do anything serious on a laptop running only on battery power.
Cushion your laptop against sub bass vibrations when playing live.
Don't ever block the vents/fans on your laptop when playing live.
Keep the laptop away from liquid spills, a roll of paper towels handy never hurts also.
Use a checklist to make sure you have all the right cables you're going to need if you are going to a 'plug n play' type gig.
Make sure you are using the most recent drivers (and firmware if your interface allows firmware updates).
If you are using a PC, make sure your power options are set to ensure 100% CPU all the time (see above re: not using battery power).
Practice with Live and keep an eye on the CPU meter, see where you run into problems with clicks/pops, and avoid pushing the CPU that far when you play live.
Remember heat can affect your computer's performance.
Before taking a daytime outdoor gig, make sure you have a way to shroud your video monitor if you want to see what is happening on the screen.
