Way to go Josh.
Your typical thrift store employee is going to be a good catch (they usually seem laid back, a little artsy not so cookie-cutter).
As you can see from some of these follow-ups, this forum has a lot of lonely and bitter men (you can easily spot them because their priority is criticize a forum member trying to better himself - rather than offer positive tips).
Best advice I can offer is to start out the conversation casual. Maybe start out by asking her about her best thrift score or the variety of customers that she sees (all walks of life go to thrift stores). Then after a some casual talk.... keep a casual tone and say something like ... "say, I was thinking of checking out that place _____ (insert new name of ... coffee shop, fun event place, bar. restaurant etc...)." Lots of forum members frown on first date restaurants, but who cares. After all this isn't a stranger on line, this is more organic. The key, no matter...is finding a spot where you're comfortable and that you think she'll also enjoy.
Then after mentioning this cool spot, follow up with "ya know.. I was thinking that we should go there this week." Then silence. This is when she'll either offer her schedule to you or make up excuses. Assuming she accepts, keep your voice at the same calm and casual pace. Then work on the time and lock the commitment down.