Go within an hour or so of opening.

I used to work right across the st from one and would spend most of my shift looking out at their parking lot and you could see it get more packed throughout the day, thin out a little bit in the early afternoon and then slowly drain towards closing.

It's always least crowded right at open and then an hour (? or maybe two?) later they open for the "regular" people and once that's the case, it fills quickly.