Envision your plan well in advance, moving furniture and cleaning up the space a week before your party. You won't be exhausted on the big day with this advice from Tori Spelling's CelebraTORI: Unleashing Your Inner Party Planner to Entertain Friends and Family.
Unless your furniture is built-in (which I doubt, but if it is, aren't you fabulous?), you have infinite possibilities to change the way the space works. If you are not having a sit-down dinner, start by moving all your dining chairs out of the party space. This lets people circulate around the table or gives you the option to push the table against a wall. You'll still use the table as a food station, but this creates more space in the middle of the room.
Assess if there is any other furniture you should move out of the space. If you expect people to stand for most of the party, remove low cocktail tables. If you are worried about overcrowding, remove standing lamps.