The two key elements to a great speech are preparation and delivery.
Speech Preparation
Make sure your speech includes the following:
1. Introduction, a body, and a conclusion.
2. Keep it short and simple
3. If you don't know most of the audience, it's a good idea to identify yourself, for example, "Hi, my name is Joe and I met Craig at football."
4. Include great memories of the bride and groom from your own past. If you'd like to make the speech funny then include some of the funny moments in your past.
5. DO NOT sabotage the groom or bride by mentioning past relationships or truly embarressing moments noone likes to be totally humiliated by a friend
6. The wedding speech should be concluded with joyful, heartfelt words. Speak sincerely and from the heart.
Have fun with your speech and prepare atleast 2 weeks prior to the big day. Write it down a few times so that it is in your memory and practice it in front of your friend or loved one. Make sure before you say your speech that you take a deep breath and if you start to get nervous just look directly into the eyes of the bride or groom while speaking. Know you are there because they asked you and trust you with this special speech anything you say will be meaningful to them.
Good luck-