1.) Turn off the ad-hoc mode on your network card (allows peer to peer connections).
2.) If you're not online, disable your network card.
3.) Make sure you have a firewall in place and running.
4.) If you are viewing your e-mail, you might want to use digital signatures to authenticate and identify yourself.
5.) I would suggest not using your credit card at a hot spot, but if you have to, make sure you're on a secure connection (for example,
6.) And, of course, it wouldn't be a security article if I didn't say, "Make sure your system is up to date!"