Depending on your relationship to the bride and groom, outline information in the following manner and be sure to keep your "speech" an appropriate length. Guests do not want to hear every detail and given too much information about the couple. It sounds too boisterous and trivial when a speech is too long. Start out by
1) Acknowledging this is a happy occasion to celebrate because...
2) State the nature of your friendship/relationship to couple
3) Tell a short history of the couples relationship
4) Add a humorous story if appropriate
5) End with a glorious wish for their happiness and new life together.