1. Update your virus protection programs every day.
2. Never click on links in emails asking you to update your banking info, Paypal info etc. Those emails direct you to sites that impersonate the original and then they collect your personal info and steal your accounts. This is the biggest source of online crime.
3. Change your passwords often.
4. Never allow sites to store your credit card info.
5. Check you accounts every day so irregularities can be reported immediately.
Lastly for real safety, use an Apple Mac. If you use a Windows PC - at least use Firefox as a browser and not Internet Explorer.
Server vulnerabilities can be plugged, but hackers always find new ones so it's an ongoing war.