Spit up

My first child hardly ever spit up, so I'm not sure if it just seems like a lot by comparison, but I feel like my daughter spits up a lot. I can't remember a time where she hasn't spit up at least a little after a feeding. The doctor doesn't seem concerned bc she's gaining weight and she doesn't seem bothered by it when it happens. But I just don't think it can be good for her to spit up that much. I sit her mostly upright to eat and for at least 10 minutes after she finishes, and I burp her after every 2 or 3 ounces. We tried the formula that is supposed to help reduce spit up but I didn't notice any improvement and it seemed to make her constipated. Does anyone have any suggestions to help reduce the spit up?