I had a smoker for a few years and used it with some success. Just bought a new one last night which I now need to assemble. Mine, unlike yours, are heated by propane. Never had an electric, but had been told that in some climates they can’t maintain the required temperature.
Here’s what I know:
Cook at low temp, 210 to 240 degrees for a long time. The lower and slower the better. And use the water pan to maintain a humid environment. Juices or other flavorings in the pan are often a good idea.
I did a brisket on my gas grill last weekend, indirect heat and very low temps. Cooked it for 6.5 hours. It was good, but would have been better with a water pan and another 2 or three hours. Just couldn’t wait any longer. That’s what prompted me to purchase a new smoker.
Perhaps another poster will have some good links for us all to explore.