Before starting the speech, know the expectations for the event. The speech's content and length are shaped by the event's level of formality, the event's duration, whether it is going to be the only speech, and who is invited.
A good speech is memorable. Include appropriate stories and jokes for the occasion. Avoid raunchy humor or using coarse language if that is not the tone of the party.
The opening is the most important few moments of a speech, so don't waste it on formalities. It's okay to use theatrics, jokes and famous quotes to grab the attention of the room, but try not to overdo it.
Avoid getting so personal that the speech becomes hard to relate to or embarrassing to hear. Unless you're speaking at a roast, don't embarrass the guest of honor too much, though a bit of teasing in good fun is acceptable.
Have a structured speech to make it easy to follow along. To avoid jumping subjects, use transitions to segue from one topic to another, keeping with the main purpose of the speech throughout.
End strong. Practice the speech alone first and then in front of someone else. Make notecards of key points to help delivery.