Your venue shapes almost every other decision, from the guest count to the colour palette. Before signing anything, ask about capacity for both the ceremony and the reception, what happens if it rains, and whether you can bring in your own caterer.
It is also worth asking how many events the venue hosts on the same day, when your suppliers can start setting up, and what time the music has to stop. Small details like parking, accessibility and a quiet room for the couple make a big difference on the day.
Finally, request a full breakdown of costs in writing. Service charges, cleaning fees and overtime rates are easy to overlook, and knowing them early keeps your budget honest.