Your Computer: Check for viruses and malware

While no virus scanner can catch 100% of infections, it is still important to run a scan on your computer with a trusted anti-virus software (or install a program that runs in the background and scans continuously). If the scan detects any suspicious programs or applications, remove them immediately.

Your Computer: Make sure your operating system is up to date

Operating systems release patches to repair security vulnerabilities. Whether you use Windows or Mac OS, we recommend protecting your computer by enabling your automatic update setting, and updating when you get a notification.

Your Computer: Make sure to perform regular software updates

Some software updates aren't included in your operating system updates, but they are just as important. Software such as Adobe Flash, Adobe Reader, and Java release regular updates that may include repairs for security vulnerabilities.

Your Browser: Make sure your browser is up to date

To check for browser updates in Internet Explorer, select the Tools tab and click Windows Update. In Firefox, just click the Help tab and select Check for Updates. Google Chrome automatically updates when a new version is released.

Your Browser: Check your browser for plug-ins, extensions, and third-party programs/tools that require access to your Google Account credentials

Plug-ins and extensions are downloadable computer programs that work with your browser to perform specific tasks. For example, you may have downloaded a plug-in or extension that checks your Gmail inbox for new messages. Google can't guarantee the security of these third party services. If those services are compromised, so is your Gmail password.

Your Google Account: Change your password

If your account has been recently compromised, you should update your password now. In general we suggest you change it periodically, following these guidelines: (1) Pick a unique password that you haven't previously used on other sites or on Gmail. Just changing one character or number still counts as reusing your password. (2) Don't use a dictionary word or a common word that's easily guessable. Use a combination of numbers, characters, and case-sensitive letters.

Your Google Account: Update your account recovery options

We all may forget our passwords at some point, so we strongly encourage that you update your account recovery options. To update these options, sign in to your Google Account by going to https://www.google.com/accounts and click Recovering your password.(a) Recovery email address: We can use your recovery email address to communicate with you if you lose access to your account. Learn more.(b) SMS: We can send you a recovery code to your mobile phone number, which you can use to reset your password. Learn more.(c) Secret question: This option is only available if you can't use the above recovery options and only if haven't tried to sign in during the past 24 hours. An ideal answer to your security question is easy for you to remember, but hard for others to guess.

Your Google Account: Turn on 2-step verification

2-step verification adds an extra layer of security to your account by requiring you to sign in with something you know (your password) and something you have (a code sent to your phone). To turn on 2-step verification, follow the instructions on the 2-step verification setup page: https://www.google.com/accounts/b/0/SmsAuthConfig

Your Google Account: Check the list of websites that are authorized to access your Google Account data

Make sure that the list of authorized websites are accurate and ones that you have chosen. If your Google Account has been compromised recently, it's possible that the bad guys could have authorized their own websites to access your account data. This may allow them to access your Google Account after you have changed your password.To edit the list of authorized websites:(1) Sign in on the Google Accounts homepage.(2) Click the My Account link displayed at the top right of the page.(3) Click Authorizing applications & sites. This page will list all third-party sites you've granted access to.(4) Click the Revoke Access link to disable access for a site.

Your Gmail Settings: Use a secure connection to sign in

In your Gmail settings, select 'Always use HTTPS.' This setting protects your information from being stolen when you're signing in to Gmail on a public wireless network, like at a cafe or hotel. Read more: http://mail.google.com/support/bin/answer.py?answer=74765

Your Gmail Settings: Check for any strange recent activity on your account

Click the Details link next to the 'Last Account Activity' entry at the bottom of your account to see the time, date, IP address and the associated location of recent access to your account.

Your Gmail Settings: Confirm the accuracy of your mail settings to ensure that your mail stays and goes where you want it to

Sign in to your account and click on the Settings link at the top to check the following tabs.(1) General: Check Signature, Vacation Responder, and/or canned responses for spammy content(2) Accounts: Verify your settings under Send mail as, which includes checking your reply-to settings, Check mail using POP3, and Grant access to your account.(3) Filters: Check that no filters are sending your mail to Trash, Spam, or forwarding to an unknown account.(4) Forwarding and POP/IMAP: Ensure your mail isn't sent to an unknown account or mail client.

Your Gmail Settings: Check your contacts for errors

Sign in to your account and click Contacts. If you don't see all of the contacts you expect to see, you can restore your contacts to an earlier time period.

Final Reminders: Watch out for messages that ask for your username and/or password. Gmail will never ask for this information

Final Reminders: Don’t share your password with other websites - Google can’t guarantee the security of other websites and your Gmail password could be compromised

Final Reminders:Keep secrets! Never tell anyone your password, or your secret question and answer; if you do tell someone, change it as soon as possible

Final Reminders: Clear forms, passwords, cache and cookies in your browser on a regular basis - especially on a public computer.

Read more: http://mail.google.com/support/bin/answer.py?hl=en&answer=32050

Final Reminders: Only select 'Stay signed in' if you're signing in from a personal computer

Final Reminders: Always sign out when you've finished reading your mail