A lot of anglers go wrong by spending too much time in one spot. If these things happen you need to get the heck out of there and go to another spot:
You only catch trash fish
If you are only catching trash fish like hardhead catfish, pinfish or whatever then you need to leave. Chances are no predators such as a redfish or speckled trout are around to beat them to the bait. At the bare minimum try switching to an artificial lure (not Gulp) that trash fish won't strike. A sparkle beetle or Matrix Shad is a good example.
You are catching nothing
If you have been sitting there for 15 minutes and haven't caught any fish and if you haven't seen any fish activity then it is time to go to another spot. If you see or catch nothing then chances are there is only nothing.
Fifteen minutes pass with no success
If you were catching fish then the bite suddenly stops and there is no activity for 15 minutes then you need to pick up and run to the next spot.
Consequences of not Moving Fast Enough
If you spend all day at one spot you risk missing out on a great fish bite somewhere else in the marsh. The absolute worst thing to do on a fishing trip is to stay in one spot despite not catching anything.