A beach wedding should be at sunset then you have the pretty color of the sun going down. There are a lot of wedding mag to look through or even go on line I bet you will find some really cool idea.
Get the bride and groom in the pre things as you can. Get them to help as much as you can it is there day. They should have to do some of the work.
I'm not sure about the bird seed on the beach they may not let you do that since it might sprout and come up or add a lot of weeds to the beach.
Having it on the beach means everyone save money on shoes.
everyone should be bare foot.