Phishing sites, which masquerade as legitimate sites, are more convincing than you might think. If you're a Gmail user, nothing might be worse for your security than giving up your Google login to a fake site.
So Google has introduced a new Chrome extension that will alert you if you enter your password on a non-Google site. It's called, plainly, Password Alert. After submitting your password to a non-Google page, you'll get a warning to reset your password.
It'd be nice if the extension could detect a fake website before you give up that precious password, but in any case this is an extra layer of protection.
Don't want to install yet another extension? Your password manager should be able to help, not just for Google phishing attacks but for other sites. When you use the password manager, it will only submit your login to the real URLs.