Gmail password can be recovered by few troubleshooting steps as discussed below.
Open the login page of Gmail.
Click on the link, Forgot Password? or Need Help?
Then provide the Gmail user id and write the code given there in the box provided.
When the user will be identified, he will be asked to provide either an alternate email id or a phone number where the notification can be send.
When user will receive the notification, he has to follow the steps to set the new password.
If user doesn't have alternate email id or phone number then he can answer few security questions which are suppose to be set at the time of creating the account. The answers are case sensitive.
If user cannot go with security questions then he has to fill a form with as much information as he can provide and send it to Gmail Technical Support team. This may take few days to identify the user and then to set a new password.
The password should be more than 8 characters long and should be alphanumeric. Password should not be shared with any one otherwise the account may get hacked.