1) open the faucet to a slow slow drip
2) observe and learn the timing until I can sort of anticipate when the water will drop off
3) set the camera to a fairly fast shutter speed (1/120 and above) to better “freeze” the action
4) use a flash unless it is very well lighted
5) focus on the mouth of the faucet ( I do this because I used a point and shoot for my water drop shots and it’s a bit harder to focus using a P&S, but if you are using a dslr then just focus on the drops) if your camera has AI servo mode then use it as it will give a sharper focus
6) Use the full zoom of your lens to avoid getting the camera wet
7) shoot away
some say that the best aperture to use is the smallest for your lens. Some tried it at about F8 but the DOF was very shallow. You can get a sharp drop at 1/200 seconds shutter speed.
but practise makes perfect, water photography takes a lot of patience.