When your lips meet, keep them slightly parted and press gently against his lips. Tilt your head slightly to one side, so your noses won't get in the way.

What do you do next? It depends. If it's just a little kiss, a peck on the lips, move away but (this is very important) don't move away all of a sudden, as if you were disgusted by his kiss! Just move away slowly, maybe while still holding hands, and looking in his eyes.