make sure u do NOT wash a non-washable hose and the other way around. if u wash a non-washable hose, it will rot.
make sure u wash the stem, base and hose well.
poke holes with a safety pin or a thumb tack. something sharp and very thin.
Use natural coals and avoid quicklights, they alter the taste somehow. Make sure the coals are "cooked" well (red all around when u blow into them)
Try to use more but smaller pieces of coal, much better than using less but bigger.
Do not overpack the bowl
Put the coals on the edges of the bowl
make sure the foil is well stretched and not directly touching tobacco, but not too far from it.
that's all I can think of for now