Venue first, then menu
This sounds obvious but is constantly done the other way round. Whether a menu is feasible at all depends on the venue: is there a kitchen, power, vehicle access, a room for setup, a plan B if it rains? A menu that is straightforward in a hall with a kitchen becomes a technical question in a barn with no socket.
So settle the framework with the venue first and pass it to the caterer. Then you get a proposal that can actually happen.
The realistic timeline
Six to nine months out: fix the venue, approach caterers, give a rough guest count. Three to four months out: tasting, settle the menu, confirm the quote in writing. Four weeks out: schedule, delivery time, setup plan and the contact person on the day. 72 hours out: final guest count.
The 72 hours are not a formality. Until then purchasing and prep happen; after that the quantity is fixed because the goods are in the house.
Where it typically goes wrong
First: the guest count is finalised too late. Second: nobody checked vehicle access and the van ends up three hundred metres away. Third: the buffet table is too small — six warm dishes plus rice needs about two metres, not one. Fourth: there is no named contact on the day, so the caterer calls the couple.
All four cost nothing if you walk through them once, four weeks ahead.
Use the tasting properly
A tasting is not only for tasting. Bring the person who will make decisions on the day. Talk about schedule and timing, not only dishes. And ask the uncomfortable question: what happens if it rains, if thirty more guests arrive, if the ceremony runs an hour late?