I bought¬† quite a bit of shisha tobacco and found all the flavours quite good and tasty, except for the cinnamon. I’ve had it before and it was bland. All shisha is flavoured with¬† oil of that particular paste.¬† ¬†¬†¬†¬† ¬†¬† I’ve added¬† a number of times usually spicce to enhance the flavour. But adding¬† spice will not be enough. You need to put some liquid glycerin in too or it’ll burn.
I use a ratio of one tablespoon to 35 grams shisha.Too  much gives it a sickly sweet taste.
To the cinnamon I added a mixture of one tablespon cinnamon,nutmeg,ginger and “hel” (cardamon) which I keep mixed up.
So what I tried was one tablespoon spice to one tablespoon glycerin mixed well, and then left it out 12 hours to acclimatize. This was my most succsessful experiment to date and it was good.
From the encyclopedia of spices if you’d like to persue.
http://www.theepicentre.com/Spices/spiceref.html
 
A favourite of mine:
DIY shisha
spicy
try putting some essental oil in the water or in the sisha itself