First, it doesn’t have to be long.  Take a piece of paper and fill it 2/3 full of stories about your daughter’s life, amusing anecdotes, and how you feel about your new son-in-law to be.  That should take care of it.  It’s actually more than you think.  Talk about your daughter’s childhood dreams, a short story about how you knew she was in love, and what her getting married means to you.  You don’t have to be a comedy act, just talk from the heart.

Do write your wedding speech out!  You don’t have to read it but it will help you keep track of what you want to say.  It will also keep you from rambling on when you forget the words you want to say.  One thing to avoid is the clichés about picking up the bill for the wedding.  They’re over used and in bad taste.  You do want your father of the bride rehearsal dinner speech to convey how you feel about your daughter’s new life.  

Practice in front of a few people and keep practicing until it sounds natural to you.  Then you’ll be ready to give your father of the bride speech at the rehearsal dinner.

If the rehearsal dinner is a formal one the toasts begin with the first course.  The host is usually the father of the groom and he will welcome the guests and thank the bride’s parents for their daughter and for hosting the wedding.  It’s your turn next as the father of the bride with your own best wishes and anything else you want to say. 

To be honest, father of the bride speeches need not be complicated. After all, you are the father of the bride so you would at least know what to say for your big speech.