Do something like a Bar & Restaurant appreciation week. Have a different special for every day. $1 lattes, BOGO or use a bounce back for free drink next time. If your going to just give a free drink coupon make it good for only certain times of the day when you are not usually busy (Bar/restaurant employees will not be morning people so late morn or afternoon will be good) Then go into the bar and restaurants and introduce yourself to the owner/manager (give him a free drink or 2) and ask that you give the coupons personally to the employees. Hopefully during a shift meeting or something similar. If you just drop them off and ask them to give them out it will not work as well.
Make them have a coupon for redemption (Though I usually am not a stickler for the date). Keep track-know how much you gave away then track how many new customers you got. Find out which restaurants were most effective and try to give them good word of mouth business, try to make them an advocate of your business.
The model can be used over and over... teachers, nurses, fireman (get a truck to park at your place), police, humane society, zoo, city/township employees, EMS, bus drivers, taxi drivers, churches etc. Don't have one every week (once a month or even better, once a quarter) and never make it so any one person can always get a coupon for your shop. You never want them to say "I never pay full price there" or "I only go there when I have a coupon"