Gloucester is easiest to enjoy when the day is planned as a short loop rather than a long list of separate stops. The cathedral, The Cross, the city centre and the Docks all sit close enough together to make that possible.
Start with the cathedral quarter, move through the centre for coffee or lunch, then head down towards the waterside when you want the more open, relaxed part of the city. It keeps the day easy to follow and avoids unnecessary backtracking.
That sort of route works well for visitors and locals alike because it shows the city at street level. Leave space for the smaller side streets and you will get a better feel for Gloucester than from a rushed checklist.