Hey, I've been doing something similar to what you're doing. I've been working at my county fair doing magic for little kids. Its new people rotating in about every three minutes or so, and i just walk around to families and perform. I've learned that simple really does hit hard. For the past four days I've done just the shake change, an ace sandwich effect, and card to mouth. All are quick and visual, just what kids need. For older audiences (teens and adult, my preference) I've also added in pressure, stairway, and doc daleys last trick. The other card tricks did wonders for me also. So to sum up, I would say pick effects you know, are comfortable with, and work for you. Stay confident and you'll be fine.
As far as where to go, I really can't help you on that part, sorry. Best of luck though!
Jacob