Retail Store Network - Best practices?

Anyone here manages retail stores network? How do you do it, and what's best practice? VOIP? POS Machines? Domain Controllers? Failover internet?

We are on VOIP Phones and if the internet cuts out or if there are some unexplainable issues there's no one there that can do simple debugging or power cycling and a lot of issues pile up.

What are ways that you have found to allow as much remote fixing/debugging as possible?

Sorry I'm a newbie, please go easy on me haha.