Kids form attitudes toward alcohol and drinking from their parents' behavior. A parent can't tell his child not to drink when he himself downs a six-pack every Friday night.
Even though drinking is romanticized in movies and media, kids are affected mostly by their own parents' beliefs about alcohol. Too many parents make drinking seem like a fun, grown-up privilege. They make drinking seem so appealing for kids who want to seem grown up. One of my sisters and her husband love to drink socially. Of course, each of their kids associate drinking with fun and they sneak drinks when they can.
I always warned my kids that anything--drugs, alcohol or anything else--that can rob you of your ability to think is dangerous. Drinking to the point of inebriation is a very bad thing. They adopted that attitude. One of my kids (an adult) will drink some but not very often. And he has never been drunk. My adult daughter refuses to drink at all. But a friend of hers became a serious alcoholic by age 18.
We talked about drinking early. We tried not to sound disapproving or judgmental. We pointed out examples among family and friends. We explained the lure of it and why kids liked it, but we always always warned them about not being able to defend yourself and think for yourself. Girls often get raped without realizing it or being able to stop it. Boys, too. And then, we talked to them about the harm that alcohol does to your brain and liver. Alcohol is a poison. The body can tolerate oderate amounts on occasion, but do you want to run the risk of ruining your health?
We taught them to rise above the peer pressure. It's so stupid. They've seen drunk people and know how stupidly they act.
An important note: we never forbid our kids to drink. We shrugged and said if they want to try it, try it. We have a drink on occasion. It took away the taboo, the lure of it. If you DO make it taboo, kids will drink to rebel and to show that they can do their own thing, if they want.