You ask people who you know and trust, about their experiences. He or his family may have a well established relationship with a florist, and be very satisfied with that florist's work. You know what I mean. It can make a big difference in your ability to communicate. Most florists will let you know if it's a bit too busy for them to go over your wedding plans, but should offer to set up a time when they can give you their undivided attention.
Some florists do cater to more expensive functions.
Don't get flustered if that is not the price range in which you feel comfortable. A good florist can create a lovely wedding and work within most budgets. Remember, whatever style you pick can be made in a wide range of prices. Some florists have printed wedding books that are provided by telegraph organizations or are sold in the trade to show you samples of styles and ideas. If a designer doesn't have such an album, don't be upset.