Tuning is one of the hardest things to do. It's so fiddly and can take hours to get just the right sound.
First of all, you have to know what kind of sound you're going for (ie: what genre you play etc).
For example, I play thrash/death metal, but also play funk and prog rock on occasion, so I want my toms to be sound deep, resonant but dampened so there's not loads of over-ring, so I have Remo
Pinstripe heads top and bottom and I tune each drum individually using a couple of guidelines I was taught by a good friend.
The batter head (the one you hit) is basically the first noise you will hear from the drum. The resonant head (bottom) is the afternote. So for example, if you hit a drum that has the batter head tuned higher than the resonant, you'll hear the pitch deepen after you've hit it. If on the other hand your resonant is tuned as tight as, or tigher than your batter, it'll produce a different effect.
When tuning a drum, it's best to start from scratch with your heads removed and starting from the highest pitched tom. Place the heads onto the drums one at a time, put the lugs on and finger-tighten. Once the lugs are finger-tight, push down on the centre of the head so that you can see the wrinkles around the edge of the head.
Tighten the head with a quarter-turn of the key <strong> across the drum</strong>. What this means is that you turn one lug a quarter turn, then the exact opposite lug a quarter turn and repeat so that you're tuning in a kind of star-shape across the drum. This will make sure all the lugs are tensioned equally. Once the wrinkles disappear, you have what I call the blank canvas. This is where you'll fine-tune your drums from.
Using the same quarter-turn across the drum technique, tighten the head until you have the right tone. Your choice of head is extremely important. It will affect every aspect of how your drums sound. For metal, you'll generally want something douple-ply or even hydraulic for a deep, dead, bassy sound. For jazz or softer music, you might want single ply, and for another type of music, another etc etc.
Play around with having batter tighter than resonant and vice versa and see what's best for you. You might think about contacting drummers you know or could come to see your kit and help you. Even one lesson with a professional drum tutor could do you the world of good in terms of know-how and technical knowledge.
I hope I've helped!
Keep playing, and let me know how you get on. Please get in touch if you need any more help; I'm contactable through my myspace or youtube accounts (below).
Take care mate