Do you use Gmail?
If yes, please, please do yourself a favor and turn on two-step verification. It will make it extremely, extremely difficult for someone to hack into your e-mail.
Here’s what it is: After you turn it on and you enter your phone number you’ll receive a text with an extra code before you log in to your e-mail. It’s easy to get your devices set up so you don’t have to do it over and over, and only slightly annoying when you are logging on to a device you don’t normally use.
The advantage? Even if someone has stolen your password they still can’t access your e-mail.
Do it. And don’t take my word for it, check out this awesome explanation by James Fallows.
Here’s how to do it (disclosure: link is to CNET, I work there).