There's a difference between not drinking and not being a drinker. If you are able to create an association in your mind between "me" and "not a drinker" it will make it easier over time to reject a drink, either when your friends or colleagues offer one or when you yourself offer one to you.

Do you want a drink? No, I'm not someone who drinks.

This technique is not specific to alcohol, I used it to stop smoking many years ago. I believe it has roots in Buddhism. The idea is to dissociate the "I" with the habit that you want to get rid of.