1. Never click on links you are not 100% sure, where they are from
2. Use Avast 5 (Free Antivirus) and Comodo (Free Firewall)
3. Always update your computer software
4. Use Virtual machines, if you have to visit a website that may be infected.
5. Don't open attachments, that claims to make you computer run faster, if you have to open use VM
6. Install a good spam filter, that way it will keep unsafe content away from your inbox.
7. Use strong passwords, some virus/worms are designed to take advantages of weak passwords.
8. Use untangle firewall to stop unwanted attacks. Since it has feautures like IDPS and a built in antivirus. These features should give you some peace of mind.