Step 1: group by affinity and age before you touch the plan
The common mistake is to start seating people table by table. Begin with themed lists instead: mother's family, father's family, university group, school friends and work obligations.
Do not try to force friendships by seating strangers with very different outlooks at the same table. Weddings work better when every guest knows at least two people at their table and has something to talk about.
Step 2: handle drop-outs and last-minute changes
Every wedding sees between 5% and 10% of guests cancel in the final 72 hours, for work reasons, the unexpected or illness.
Keeping the seating plan in interactive software like MisePlan lets you move a guest or tighten up a table in five seconds, without redrawing the whole layout or crossing names off a paper list.
Step 3: get the allergen and special-menu report to the caterer
The maître d' and the chef need to know not just that there are 4 coeliacs and 2 vegetarians, but exactly which table and which seat each of them is in.
A good routine assigns every special dish a table and seat number, so the waiter serves the right plate without having to call out «who was allergic to nuts?» across the room.