1. Login to your old gmail account. Go to Settings > Forwarding and POP / IMAP. Choose Enable POP for all mail.
2. Then, login to your new gmail account. Go to Settings > Accounts and Imports. Choose Add POP3 email account.
3. A box will pop up. Fill in the old gmail address, username and password. Change POP Server to pop.gmail.com and leave others to default setting. Click Add Account. The transfer process will start and it will take some time based on your old gmail data size.
