1. Don't hold a party in public view where police can easily witness the unlawful activity taking place.
2. If the police come knocking due to a complaint regarding said party, quietly have guests put any alcohol out of view.
3. Come to the door, exit the house, and close the door behind you before talking to the cops.
4. Respectfully decline if the police ask to come in to investigate. If there is no warrant or exigent circumstance, it may be unlawful for them to enter.
5. Don't talk to the police beyond asserting your rights.

I am not a lawyer and people should seek legal advice before throwing a party like this.