When I have to take a break from my computer, I try to remember to log out before I leaving it completely. I don't want any hackers to have field day with my personal information.
Another lesson I learned is not to click on links that I don't know, because the links could lead me to download a virus that attacks my computer system. Yes, I had this happened to me before from clicking on a link in a search!
There are many other things you can do to protect yourself, but for starters try these ten things on Protect Yourself | Internet Security.
Have a wonderful Monday!