I have seen problems of low smoke on the following:
1. leaky hose
2. badly placed foil over the bowl or too little holes on the foil
3. to much tabacco wedged into the bowl.
4. bowl not attached properly to th hookah
5. Hose not properly connected to the hookah
6. Coal imporperly placed - make sure the choal is fully light up and not black - place the coal flat side on bottom - allow to sit for 5-8 min on the bowl
7. Depending on the coal and where you placed it you may not be generating enough heat.