"Fluff" the tobacco, make sure there is good airflow. Also watch the heat management, too much and you will scorch the bowl at the very beginning (in other words don't use too much coal).
Watch this video on how to setup made by Sambooka http://youtube.com/watch?v=k_BCJ1xOQTE
and also take a look at this for fixing harsh smoke http://youtube.com/watch?v=2zvN1cL1uik
Hope that helps.