R.A.
I have a 15 month old, and she tries to hit too. I just say ouch in a sad voice and tell her don't hit, baby! in a gentle voice. I try not to make a big ruckus since she likes the attention it gets her. If she continues, I get stern and hold her arm down by her side. If I'm holding her, I put her down to sit on the ground. She usually gets upset that I won't hold her. I think that this age will learn that all the fun goes away with that behavior, and they seem to stop. I do know that with my other two it was just a phase, and they outgrew it in a couple months. We responded the same with them.