One of the most important things to remember when giving a wedding speech is that it needs to be kept short and sweet. Many people have the tendency to go too long when they get nervous. Writing the speech and practicing it ahead of time can help make sure that it is kept at an acceptable length.
The speech should also be appropriate for the audience. Stories and jokes told need to be acceptable for both family members and friends of the couple to hear. Telling a story that makes the family or couple feel uncomfortable is a sure way to kill the mood of the event.
It is best to keep the speech lighthearted and fun. Keeping the focus on telling stories that represent exactly what the groom and bride are about. It is also highly important to remember to wish the couple the absolute best throughout their lives together. It should not be a speech focusing on the couples past, but instead a speech sending them off into their future.