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Check your water level - it all depends on the hookah base but you should definitely evaluate that you have enough water or else the session will be too hot to smoke! A little more than halfway filled with water is recommended. You can also choose to add ice if you want a kick to it but keep in mind the water level.
Check your connections - anywhere two parts come together on your hookah is considered a connection and they should be checked that they are actually connected properly and securely. This includes the hookah hose, base, bowl, hookah accessories, ball pin, etc. It is wise to do this check at least once a week or even daily depending on the amount of use your hookah goes through on a daily basis.
Heat your coals adequately - make sure to use coals that have been properly heated until glowing or else you can find yourself smoking hookah charcoal flavored shisha soon. It is also important to periodically flip and rotate the coals in use while smoking, especially long sessions.
Packing issues - this is a key component in any hookah session and will slowly become second nature as you practice packing a bowl. Re-check your bowl if you are having any issues, it could that it is over or under packed and will require a re-packing before being able to be smoked.