For those of you reading this who don't know me, I will agree in advance that it could seem like a gratuitous plug for wedding planners. But what I am about to tell you is based on real, quantifiable numbers.
If you are considering hiring a wedding planner (or even if you aren't), do it BEFORE you book your venue. Wedding venues like to work with wedding planners, because we speak the same language and share the same concerns. Sometimes, weddings without planners rely on the venue to help with details that are really beyond the scope of their role. Many wedding venues will offer a discount, allow some flexibility with minimums or throw in extras when you are working with a wedding planner.
Not all venues offer savings for working with a wedding planner, but many do. If you are considering a planner, hiring one before searching for your wedding venue can often deliver an immediate return on your investment!