Drums need to be tuned as do any instrument and as with any other instrument they do not like over tightening. As you progressively tighten the skin the drum has a number of different times when the shell resonates well with the frequency produced by the skin, the most important thing however is that you like the sound of your drum and enjoy playing it.
Important - tune your drum when it is warm and dry not when its cold and damp as it will tighten as it warms up and may split if overtight
You will know your drum needs tuning when it sounds flat and lifeless
1/ Choose the next two zig-zag strings to tune, i.e. numbers one and two.
2/ Take the tuning string over those two strings, round under number two and up between the two.
3/ Take the tuning string back underneath strings number one and two.
4/ Pull on the tuning string, if you have it right they will cross over and hold.
5/ Repeat with the next pair of strings and so on till the drum is tuned (play the drum as you go to hear the effect).
6/ When you complete one whole ring of tuning (after a period of time) you need to move up the drum to the next row, to do this miss one string and go on as before.