Official Google Blog: How to avoid getting hooked

Take preventive measures like
1.Be careful about responding to emails that ask you for sensitive information.
2.Go to the site yourself, rather than clicking on links in suspicious emails
3.If you're on a site that's asking you to enter sensitive information, check for signs of anything suspicious.
4.Be wary of the "fabulous offers" and "fantastic prizes" that you'll sometimes come across on the web
5.Use a browser that has a phishing filter.