Hey guys thanks for the reply. Well where to begin. I'm using a Great Outdoors / Smokey Mt. Series propane smoker. I've used a couple different recipes for rubs and they are either too spicy or salty and have varied the time the rub is on. The BBQ is usually dried out. I didn't trust the thermometer on the smoker so I dropped a internal one thru the top vent ant tried to manage temp that way and there seems to be a 20 degree difference. I tried to smoke ribs (beef and pork) chicken quarters, fish and a pork picnic. Got a big family reunion in mid April. Boy if I could smoke some good pulled pork I would be stoked.
Try using a commercial rub as you are starting out in your quest for great Que. Go to BBQ Island and get yourself some Plowboys Yardbird for pork and CHX and some Butchers Premium BBQ rub and /or some Dizzy Pigs Dizzy Dust. These rubs are great baseline rubs to work off of as you make your own rubs.
As for dried out meat, try foiling ribs, brisket and pork butts at some point during the cook. A good guideline is to foil at: Ribs 3hrs (spares) 2hrs (BabyBacks), Brisket - once internal temp hits 165, Pork - once internal temp hits 165. Try brining your chicken to add moisture to it. Kosmos makes a great product for brining CHX as well as for injecting beef brisket and pork shoulders.
I don't know where the temp gauge is on your smoker, but try to take your temp readings at grate level. A Maverick ET 73 is a decent thermometer that will do the trick nicely. Your 20 degree difference could be due to the different levels at which your thermos are reading or it could be due to a bad thermo.
Also, learn about injecting briskets and pork butts. There are many great recipes on the internet and they will add moisture and flavor.
Lastly, I wouldn't recommend smoking fish with other meats. It tends to add a fishy taste to other meats.
Good luck.