It's difficult to discuss a book with someone if they've never read it - it's the same with your wedding. If you and fiance have different visions for your big day, then there will be more arguments then there needs to be.
Talk about your dreams and where your focus is. It's hard if one of the two of you really doesn't have much input. But even small discussions help.
If each of you write down 5 of the things that are most important to you for your wedding, or 3 adjectives describing what your expectations are - that might help.