I'm right there with you. I've had a ridiculous amount of flats on my "other bike". Everything on that bike is brand new except the wheels. I checked the rims with a cotton ball as someone suggested and didn't find any sharp edges. I put new rim tape in and still got a flat within a day. They were cheap no name rims that came off my old $200 fixie so I'm hoping the new wheels I just bought will fix the problem. For the record I've changed out tires and tubes on my commuter three times now just trying different tires and have had zero flats so I don't think it's something I'm doing wrong....but who knows. Good luck and if it keeps happening I would swallow some pride and go to the LBS and have them fix the flat and see if the results are any better.