A divorce party is a chance for someone to celebrate the wide-open potential of their next phase of life. It's also a way to release the past and move forward with a clean emotional slate.
Don't make the mistake I made: If you want people to show up, you need to give them enough notice! In general, it's good etiquette to give local people at least two or three weeks' notice. Try to give long-distance friends at least six weeks' notice to make travel plans.
In terms of your guest list, here's another mistake of mine to avoid: Don't cast too wide a net. A divorce party is an ideal chance for the people closest to you to show their support. It can get awkward if the room is full of casual acquaintances or plus-ones you've never met.
Ideally, a divorce party is a chance to set the tone for what's next-and that can be a guidepost for your party-planning decisions.