You can select your Free/Busy calendar from the list of calendars and make your Free/Busy information more precise. When others view your Free/Busy information, it will help them to schedule events based on your information.
- Click on "Settings".
- Select "My Calendars" from the left pane.
- Click on "Details".
- Enable the check box "include in my Free/Busy sharing".
- Save to update the changes.