Make sure the bag you bring this stuff in is a beach friendly bag that lets the sand fall out through loose knit threads, like a net. Also if you have clothes with pockets like that, bring them instead of clothes that have pockets made of tight knit cloth.

Also bring something to put seashells into for the trip back home. Maybe a plastic jar.

A bucket is always a good idea. You can find collapsible buckets that would be easy to fit inside a bag. Buckets are good for sandcastles and for bringing water to wash sand off of things.