1. If ever it seems that the account has been hacked, then immediately reset your password. Never use passwords like Mobile Number, Date of Birth etc. It's better to set the alphanumeric password.
2. Continue to scan the virus from time to time in your Smartphone, laptop, and tablet. The account can also be hacked due to the virus. Here's how to keep the phone virus free.
3. Keep track of the recovery option of the account continuously. The mobile numbers and email IDs mentioned in this are those you still use.
4. Use 2-step authentication. This doubles the security of the Google Account. Go to https://www.google.com/landing/2step/ for
5. Keep your web browser up-to-date too. Also, use a third-party anti-virus device in the device.
6. 6. Do not use the same password in Google Accounts and elsewhere.
7. 7. Lastly, do not share information about your account with anyone.Gmail Phone Numberclick here for link