I can't remember if I already told you this, but def check out Sambooka's, How to Set Up a Hookah Tutorial on YouTube. Here's the link.
Check that out and set up your hookah. I also was wondering how you plug the other two valves on your hookah. Do KM's use ball bearings, or do you have to get a rubber stopper for the valves? Make sure the valves are also closed air tight. Also do you use a grommet with your bowl? A grommet is the little elastic plastic piece that goes on the top of the hookah and helps ensure that there is a nice tight seal between the top of the hookah stem and the bowl. The same goes with the grommet that attaches the hookah stem to the base. I think everyone else covered the tips about brand/quality/moistness of the tobacco and coal. One more thing about the coal is that you wanna make sure that it's red hot, and has no black spots. This could be a factor as well. Whenever I use quick lights, I still light them on a gas/electric stove to make sure of that. Obviously since they're quick lights, you can use a lighter, but just make sure they're red before you put them on the foil. If you smoke and have access to a gas/electric stove, I would advise you to use natural coal because I think they provide better heat, and burn less slowly that quick lights. I prefer Exotica Natural Coals by the way, and you can check out Sambooka's review on those too. Here's the link.
I hope I helped you out. Enjoy your smoke sessions, and as always if you have questions, just post, and everyone here will be glad to help out. Take it easy.