I shoot a Mossberg 500, basically the same gun you have. I've killed plenty of turkeys with the standard full choke. I'm going to an extra full this year, for a bit tighter pattern. I shoot Win 3" #6 loads. These have never failed to kill one yet.
I generally carry a couple slates (one a crystal surface and one slate), two box calls - one with a very high pitch, and a couple diaphram calls. You should have a way to call even in bad weather, so sometimes the mouth call is all that will work. Plus they are hands free.
Use whatever camo you have. I like to mix/match tops and bottoms actually. I try to set up with a good backdrop and a little screening vegetation/brush in front of me. The backdrop is very important as you will get spotted if you make a silhouette. A tree or stump that is wider than you are is good, but other objects work too. Also, some margin of safety is afforded by a solid backdrop, as the only knucklehead that could "mistakenly" shoot at you should be where you can see him first.