If parking is full keep driving north on Gulf Drive
If the parking lot it full as it was for us on a recent visit, keep driving north on Gulf Drive, which zig-zags up the island. As you pass each street, look to your left and you'll see beach access points at the end of each street. The higher up you go, the less busy. Keep in mind: these are residential neighborhoods. You are allowed to park on these streets and use the access points, but park legally (not too close to driveways, facing wrong way, etc.) They will ticket illegal parking!