Plug in SEO Plus comes set up out-of-the-box for generating good structured data for your shop. There are a few additional things you can do to enhance it.
In your Shopify admin go to Themes > Customize theme > SEO - Structured data.
Add a logo image and check 'Include logo?'.
Social Profile Links
Include URLs to all of the social profiles you have, one per line. Note that, as you can see in the image below, the text will wrap (go to the next line). Just make sure that you press return after each of them.