A ton of people have already given you suggestions. I don't really feel like reading every single post to find a tip to give you that no one else already has. So here goes nothing;
It could be your shisha, some of the major cloud providers are AF and SB, as well as others that I am too lazy to list.
Mmm, Holes in the foil! Make sure they are a decent size and you are getting good airflow, if not you could be bottle neckin' the air circulation, causing weak clouds.
Coals! Make sure you are getting enough heat to the bowl but not too much!
Make sure your bowl is packed right, not too tight, make sure you can get some air!