I've found having something tall at the back helps it sets the scene and you can see it through the munchies and bottles. I've used fake pumpkins and faux grave stones for height.
Using some Halloween themed serving items makes it FUN too. Last year I found the Blooding skull punch set at Wal-mart for $25. Talking skull tray is a BIG hit. I've bought after Halloween all the glasses At Walgreens for about .50 cents, before Halloween they were $1.99. I've slowly collected more every year. The after season sales are a real deal! The next year you'll have a KILLER table!