I agree with this, but I'd simplify even further: Get two friends to play the role of bartender, buy a few cases of beer, and do this at home. Invite 10-15 frie

I agree with this, but I'd simplify even further: Get two friends to play the role of bartender, buy a few cases of beer, and do this at home. Invite 10-15 friends over and ask them use your app. Watch them use it, and ask lots of questions afterward. Make sure you have a small set of specific questions you want to see answered by your user study.