I've got an XL40
Masterbuilt single door propane.
It's basically a cabinet with racks and a burner in the bottom.
About a as basic as it gets.
I had lots of problems and solved most of them...
One issue was temp control so, as suggested by many on this site, I installed a needle valve to my propane tank that gave me better temp control for lower temps...if you're too cool you'll have to look into adding some insulation...my issue was getting cool enough.
The next issue was hot spots.
From top to bottom and front to rear I had as much as 30-40° temp differences...
I got a piece of 1/4 inch thick sheet steel about 14 inches X 24 inches from a scrap yard...filled the water pan with sand and set the steel directly on top of the shelf that holds the water pan making a big heat sinc. It helped alot but I still had some hot spots so I drilled 3/4 inch holes in all four corners through the side of the cabinet for air flow (8 holes in all, 4 in each side) I use flat refrigerator magnets as dampers to choke them down...
After playing around with them I all but eliminated hot spots.
SMOKE...Yup...same problem so I got an A-Maze-N tube and abandon the chip tray altogether...
I mix in hickory chips with a competition blend of hickory, maple and cherry (HMC blend) pellets from lumberjack...the pellets alone didn't seem to impart much smoke flavor but adding chips (about half and half solved the problem.
I ran into another problem though...
keeping the tube lit...so I took two small pieces of 2x4 wrapped in foil (to prevent burning) and put one in the front left corner and one in the back left corner right on the floor of the cabinet where I set the well lit tube...I then drilled 5 more small holes about the diameter of a pencil right along the side where the tube sits...and now it smokes away for about 4-5 hours...
Sounds like a lot of stuff but it's all pretty simple stuff and my smoker works amazingly good now.
Not knowing about your particular smoker I'd just start with the needle valve and a smoke tube...and go from there...
Hope some of this helps.
Good luck and happy smoking.
Walt