Get there at least 3 hours before low tide.
I was there yesterday, pulled onto beach and drove a few hundred yards and parked.
Kids played in the sand, and had lunch while I walked the waveline keeping an eye on the sand...
As soon as we saw the first "show" it was about 45 minutes before I had 90 clams (4 kids and 2 adults) in my cooler and on my way home at 4:00.
Other people were just getting there, as low tide was not until 5:00.
This was from the beach access right in the middle of town.