Spread a bit of petroleum jelly or silicone grease on the threads of the stem to lubricate the faucet's action. If the faucet leaks around the stem rather than from the spigot, install new packing. Use three complete wraps if you're applying string-type packing. Some stems use O-rings, rather than packing. For these stems, replace the O-ring with a matching one to stop a leak.
Hand tighten the packing nut, then tighten it another half-turn.
A noisy washer-type faucet is usually caused by a loose seat washer. To stop the noise, first turn off the water and take the faucet apart as described previously. If the washer is loose, tighten it or replace it. After threading the stem back into the faucet body, try moving it up and down. If it moves, the stem is worn and the entire faucet must be replaced.