Book venue (or rent a tent!)
Invitations
Hire caterer and plan menu (buffet style or formal dinner, drink menu, dessert)
Welcome/entry signage
Sign-in board or guest book
Overall room décor (balloons, banners, lighting accessories, etc.)
Seating cards
Table décor, including linens, place settings, glassware, centerpieces, votive candles, napkins/napkin rings, etc.
Confirm DJ or band
Confirm photographer and/or videographer
Design and print personalized or professional programs if needed
Create "day of" schedule and name a day of coordinator
Confirm headcount and go over last-minute details