Exporting your Google contacts is a fairly straight forward, just follow the steps below.
Log into Gmail.
Click the Gmail drop down and select Contacts
Select More then Export
Select the Contacts you wish to export, select Outlook CSV format then click Export
The file will start downloading immediately to you default download location. You can then import the file into Cliniko using this guide: https://support.cliniko.com/entries/21337004-Importing-Patient-Details