Congratulations! Let's start with the three basic principles of the: Father of the Bride Wedding Speeches - How to be Witty and Well Prepared!:
There's nothing wrong with a 15-second "Here's to my lovely daughter on her wedding day, and her wonderful new husband!"
Your daughter truly does not want her boss, her new mother-in-law, and her 8-year-old niece to know about how, at age three, she wandered into the living room naked and asked embarrassingly personal questions of your guests. Think "celebration," not "humiliation."
Comedy is difficult. There's nothing wrong with being light- hearted, but resist the urge to toss in a few deliberate "laugh lines." Without expert timing behind them, jokes usually fall flat.
Bearing those principles in mind, how do you organize your speech?
When you prepare your speech, the best place to start is by making a list of what marriage means to you. Brainstorm with your wife what qualities have been necessary to a successful marriage, what lessons you've learned together, and what words you would use to define a happy marriage. Once you have a list, choose three ideas that seem most important. Build your choices of stories around those ideas.
If that approach leaves your mind blank, you can also go the other direction: make a list of the most memorable moments in your daughter's life, and then use those stories to help you think of traits that you want to emphasize.
The best speeches-the ones the audience enjoys most-are usually spoken with an appearance of spontaneity, not read from a script. Try outlining your speech, then practice from the outline, improvising the words as you go. Only if you are an extremely nervous speaker do you want to write the full speech word-for-word and memorize it. Resist the urge to bring a stack of notecards to the wedding-reading your speech cuts you off emotionally from the audience and greatly decreases the impact of your speech. A wedding is an occasion when simple words spoken with sincerity are much more moving than fancy phrases.
Be sure you practice for several days before the wedding, if your speech is more than a quick toast. When you deliver the speech, take a moment before you start to look into the audience (not above their heads) and let their attention collect on you. Don't rush, and remember to breathe!
Finally, make sure you end strong. Don't just run out of things to say. If you end with a toast, a simple "To Monica and Howard-may they enjoy many years of happiness together!" is all you need. If you don't want to end with a toast, do something else: hug your daughter, kiss your wife, or announce that dinner is served.
That said, relax and enjoy yourself!