One thing we've learned is to never write down your passwords. This seems so obvious but I didn't realize how important it was until it was emphasized in class and websites. I have a horrible memory and I always write my passwords down because if I don't I never remember and have to reset it or getting it sent to my e-mail, which is just a hassle. I've realized the hassle is worth it instead of getting my credit card information, bank statements or e-mail hacked. We also learned what constitutes a safe password, such as making it at least 6 characters, using upper and lowercase and both numbers and letters.
I once saw a TV show where a wife spied on her husband by tracing his keystrokes to track his e-mails. I thought this was so unrealistic until we learned in class that there actually is spyware to trace that. Then, when I was filling out my FAFSA information, I saw a real life application. Instead of typing in my social security number, the website offered a keyboard on the screen that allowed the mouse to click on the numbers so keystrokes couldn't be traced.