• Menu
• Drink list
• Choice of table linen
• Décor on chairs
• Ballroom décor
• Backdrop design
• Table centerpieces
• Floral arrangements
• Music & entertainment
• Favors provided

Once the above is in place, start selecting the guests invited to sit at the main table:

1. Groom
2. Bride
3. Groom's Father
4. Groom's Mother
5. Bride's Father
6. Bride's Mother
7. Grandparents?
   
8. An aunt and uncle perhaps?

But you can always keep it to lesser than 10 pax at the main table to avoid controversy. No need to be legalistic about it.