Know your intent. If you are planning a party know what you want. Be clear with why you are having it. Is it to celebrate another persons life, is it an open house, is it a Wedding, a Bar or Bat Mitzvah?
Personally, I think parties are about joy and celebration for milestones, achievements and life changing moments.
The most important outcome for a party, any party is fun. I think as a host it is part of your job to think about your guests and their comfort. Happy guests means happy party.
In my opinion one of the best ways to inspire your guests to share and participate is to make them feel welcome:
If parking is a problem hire a valet.
If it is cold have heaters or shawls.
Greet your guests at the door with a specialty cocktail to help them settle in.
Remember, the purpose of your party is to celebrate. Welcome your guests into the party and let them know how happy it makes you to have them there with you. They will reciprocate in kind. Happy guest mean a party that has a packed dance floor. What more could you ask for?