Suggested contacts include people you've added to your contacts. People you've interacted with in Google services are automatically saved to "Other contacts." Tip: You can stop automatically saving contacts at any time.

Suggestions are based on a variety of signals related to your contacts and interactions, such as a contact being starred or if you've emailed a contact recently. Suggested contacts include people you've added to your contacts.

If you're not already in Gmail, just visit contacts.google.com in your browser. You can even bookmark it for easy access. If you are already in Gmail, you can use a keyboard shortcut (if you have them enabled - check in your settings menu). Just type G followed immediately by C and the contacts page will open up.

Frequently contacted: Here, you'll find a list of the people you recently communicated and collaborated with in other Google apps. That includes people you've emailed in Gmail and worked with in Google Docs, for example. You can add new contacts directly from this screen.