It can't be one of your favorites. You'll just get mad when they talk over the music.
Put the records in order at the front of your rack. If someone wants to feel useful by queuing up the next one, let him. When he flips through the back sections, reach in and pull one out. Have you heard this? The trumpet player's the same as here. Waggle a finger at the turntable. Smile. Offer to accompany the helper to find a refreshment.
The B sides will be slower. That's good. Let a particularly slow B side lead into another B side, not an A. Make sure nobody's yawning or sighing.
Prop up the jacket; lean it against the turntable's lid, and watch for when people linger to read it. Sometimes, when someone needs a pal, the record player's their parking spot.
A familiar song or three spread out over the evening is nice. It gets them talking: I didn't know they did this one, too! Is this the same group? But any more and it's a singalong. That kills the conversation. The music is not a guest.
When it's time to put out the coffee, the music will tell you so. Send people off feeling warm, but don't let the record make invitations for you.