Answer:
- Make sure you are behind a properly configured firewall.
- Use a secure operating system, such as Linux, or if you must use Windows make sure that you have anti-virus and anti-malware programs and that they are up to date.
- Keep up to date with system patches.
- Use strong passwords and don't tell them to anyone (and don't put them on a post-it note attached to your monitor).
- Try not to use the same password for different services.
- Don't run unknown programs or visit untrusted websites.
- Beware of email attachments (even from friends) and emails that claim you need to log in to your bank/paypal/ebay/etc. account. If you suspect an email may be fake, type the address into your browser manually, DO NOT click on the link provided.