Lots of good advice, so far.
The WSM doesn't need a lot of seasoning. however, you do need to cook out the oils and such that come from manufacturing -- or wash them out with dish soap (Dawn) and water.
I got good results on my very first cook, which was a few racks of spares. A pork butt is another good first cook. Fatty meats are good to start with, IMO.
Get it up to temperature for a while before you put any meat in it for the first time, just to make sure no funkiness is in there. I used nothing but charcoal for the first 30 minutes or so, and sniffed around it a lot, to be absolutely sure I didn't smell burning oil or other unnatural smells. Then, I added my smoking wood and started my cooking.
I may have gone overboard, but the food was good on my first cook, so if I went overboard, I can live with that.
After the first cook, I mixed my smoking wood chunks in with my charcoal. Like others have mentioned, I use the Minion method. That method is perfect for a WSM.
Other than that, just pay attention and learn. You should get good food on the first cook, but the more you use your WSM, the easier it will be to get good results. You should get more and more comfortable with every cook.