Hank brings a wise word about experience, which makes me think I should amend my earlier post.
One really important thing I've learned the hard way (again, and again, and again) is that you have to 'ease up' to temp, whether on a kettle or a WSM. Pay a lot of attention at the beginning of the cook as you are coming up to temp, and be assertive and aggressive about clamping down your vents pretty tightly *before* you get close to the range you're aiming for. Give yourself at least 25 degrees of space to ease up to temp, and even more if your temps are rising quickly.
This is important when using briquettes, and it's essential when you're cooking with lump. That stuff will start to burn like an inferno if you go inside to check the WKC for an inopportune few minutes. And heaven help you as you try to get it to cool down.