clean the hookah after every smoking session right away so that the gunk and dirt do not have a chance to dry and make the job 5 times harder.
You MAY use a light solution of soap to clean the shaft and bowl but not the hose. (Washing dishes never leaves residue does it?) Once every 10 times is enough.
change the water which filters the smoke every time.
Check the inside of the shaft and bowl for impurities If so use your hookah brush and clean the shaft and bowl, clean off the ball-bearing in the air release valve.
Blow out the particles which may be in the hose.
Don't use water inside the hose which will rust out the metal support coils unless you KNOW that its a genuine washable hose- and most aren't. Blowing air should be enough.
You could buy a different hose for each flavour, or at least a few for extra strong flavours like mint and double-apple, and one for all the fruit tastes.
Its worth investing in great hoses since the quality will affect the taste and thickness of smoke.