A leaking faucet can often be fixed by replacing the o-rings inside it. There's likely a protective cap holding the handle's retention screws secret ;) As lemonie says - turn off the water supply. Pry off any covers, unscrew and remove the handles..., then look for a large (usually brass) nut holding the valve assembly in the faucet base. Once removed, look for the rubber o-ring. It's likely compressed, or cracked. Get a new one from the store, costs 1-2 dollars. Lubricate it with some petrolium jelly for ease of installation, then reverse the steps to reassemble. I can't be more specific without seeing what type of faucet you have.