One of the best things about having a wedding on the ocean/beach is that you have all the reason in the world to incorporate starfish. Who doesn't love starfish? In this photo, starfish were used not only as favors that guests to take home with them, but they served a second purpose, as placecards for guest seating at the reception. This is a super-easy thing to do yourself. Buy the starfish (great website is www.seashells.com), print the guest name and corresponding table number on a card, and attach the card to starfish using a thin ribbon that coordinates with the rest of the the colors of the day. I've also used natural raffia for a very organic feel. Colored raffia works well, too.
The tray in this photo is actually a clear, plastic picture frame. Turn it over, and it's a tray. The sand is a key element here, and you have to get it right or the whole project will be a disaster. In my opinion, craft sand works really well. You can buy it at craft stores like Michael's. What you shouldn't try is sandbox sand that you buy at Home Depot. It's moist, heavy, and it clumps. You may assume that you can just use sand from the beach, but I wouldn't. You'd be surprised how dirty beach sand is when you bring it inside!! Another key, buying enough of the craft sand. You'd be surprised how much sand it takes to fill a tray deep enough so that the starfish can be propped up in it. If you're not using a wedding designer/planner/coordinator and you're doing this all yourself, remember to alphabetize the placecards by last name. You'd be surprised how many brides forget to do this. Without alphabetizing, there's no rhyme or reason to the display, and your guests will have a hard time finding their name and moving out of the way for other guests to find theirs! This will result in a bottleneck at the entrance to the reception (escort table).