Smoking and drinking is dangerous to health. And it creates problem in between your relation. So try to keep away it.
Why not have a glass of wine ? I mean - come on - not like getting drunk - but why not have a glass or two?
If your date is attractive,then stay sober. But if they are ugly then start drinking. The more you drink,the better they will look.
If drinking is a normal part of your social outtings, then yes. If it is not, then no...don't use a drink to "loosen you up". Let your date see you for how you are, that is the point of a date.
I think its not a good idea First, you need to meet very well the other person in addition if you drink a lot you could give an incorrectly impression from you Keep your senses alert analyzing everything around, later you will have opportunities to drink and to do another things