Your First Instance: Taking A Snapshot
Time Required: 5 Minutes (Mostly waiting for snapshot generation)
Once you've completed the Initial Server Setup, shutdown your instance with:
sudo shutdown -h now
You can power off your instance from your provider control panel (The Power sub-menu for your droplet on DigitalOcean) but it is always best to do so from the command line. (Note: On occasion, you may still have to power off your droplet from the control panel, even if you shut it down from the command line)
Select your template Droplet:
Then select the Snapshots menu and enter a name for your template snapshot. By default, the snapshot will be named after the instance, followed by a unique code; You can remove the trailing -code and just call it template since we'll be destroying our Droplet with the same name in a moment and left with only one thing called template. 
Now that we have a snapshot we can use to build all our future Droplets, we don't need this one anymore. Select the Destroy submenu for your Droplet.