I sort of created a baffle with a water pan. I placed a cake-pan sized water pan on the first rack right above where the heat comes in from the firebox. I think this helped distribute the heat and at the same time provided some moisture and helped with temperature control.
I should mention how I suggest firing the smoker.
I fill the coal chamber about half-way with unlit coals, positioned towards the smoker, and forming a bit of a ramp. Then dump a 3/4 chimney on the other side. This seemed to work well, bringing up the smoker to about 225 and holding there for about 3 hours, I didn't really have to do anything. The unlit coals slowly lit over time. This was in full sun on a 90+ day, so that helped.
I suggest these steps:
1) Fill chimney 3/4 full. Light, and wait for 3/4 fully lit. Don't want to see any smoke off the coals.
2) Dump that in the coal box, up agains the unlit coals
3) Wait for smoke from coals to become clear again.
4) Put your meat on
5) Throw some wood on hot coals
The reason for steps 1 and 3 is you don't want to smoke your meat with smoke off the briquettes (assuming you are using briquettes). When they are hot enough, they stop putting out smoke.
Disclaimer: I've only done one smoke on this smoker, so your mileage may vary!