Heh I have a funny story on this:

My buddy (non-drinker at the time) had a job that required him to grease the wheels with clients and a major lubricant was alcohol.

He came up with an idea: cranberry juice in a wine glass

Everything seemed to be going swimmingly well, till one of the senior clients came up to him and whispered in his ear: "it works better if you don't put ice cubes in there" :)

Anyway, he started drinking pretty quickly after and hasn't looked back since.

This is perhaps the most effective thing to do, and yet we don't do it because deep down we want people to respect our choice to refuse to drink.