Seat guests next to people they share a surprising, non-obvious overlap with, found in advance, and invite your closest people first.
The idea
Jayson Gaignard, who founded Mastermind Talks and wrote Mastermind Dinners, says the heavy lifting of a dinner happens before anyone arrives, in choosing the people. A dinner is really a long string of introductions, and each one should be relevant. What he looks for are "uncommon commonalities": overlaps you'd never spot from someone's name and industry, and the deeper the overlap, the stronger the bond. Jayson has hosted well over a hundred dinners and still worries each one will flop. His fix is to stack the deck: invite his existing peer group first, which gives him the vote of confidence he needs before reaching out to people he isn't as close with.
How to do it
Invite your closest people first. For a dinner of 20, Jayson finds it a lot easier when he's already close with the first 10 he invites.
Learn about each guest ahead of time. When he can, Jayson has people fill out biographical forms before the dinner.
Look for the overlaps you can't see from a name and an industry.
Assign seats so those people sit together.
Example
For one dinner in LA, Jayson seated two entrepreneurs across from each other. What they didn't know going in: both used to race mountain bikes professionally. Sitting face to face, they had business, biking and family to talk about.
Curate Hard: Who's in the room makes or breaks an event. Curate the guest list carefully and pick a venue with character over the default ballroom.
The Four Points of Information: Four places good notes come from: where the relationship stands, where their work stands, next steps, and personal details. Keep only what you'll use.
The No-Ego Dinner: Keep the guest list secret and hold off on professional introductions until the next morning, so people meet the person instead of the title.
Second-Degree Dinners: Co-host a dinner with one other person and each invite your own guests, so half the room is new to each host.