Tip 1: Write your speech. Make it honest and sweet, filled with personal anecdotes about the person you are honouring. Now pepper all the honest sweetness with lewd one-liners you found on best-man wedding-speech websites (e.g. "Fornication! ... oh sorry, I read that wrong ... For-an-occasion such as this ... ")
Tip 2: Half an hour before delivering the speech, find a quiet corner to collect your thoughts, focus on the task, and get drunk. Not mildly drunk; we're talking completely hammered, until you can't stop grinning and it takes five tries to say "cash register".
Tip 3: Seconds before giving the speech, take off your glasses so you can't see anyone's faces. If you don't wear glasses, put on a pair of someone else's. Now you'll be speaking to a roomful of blurry pineapple shapes with honeydew heads. Not only easier; kind of cute.
Tip 4: Say funny stuff about the person. If you can't think of anything, just imagine something funny and laugh uncontrollably (baby sloths in a bucket). Also say some sad stuff. If you can't think of anything, imagine something sad and start to cry (baby sloths in a bucket, most dead, a couple very sick).
Tip 5. Keep the speech short and get off – don't wait for applause, there won't be any. Find a quiet corner to wind down, debrief, and get even more hammered, so you won't notice that no one's talking to you for the rest of the night.
Sometimes it’s fun to talk about the opposite of what to do. I did that back in June 24, 2008 in a blog post on Don’t be a “Flip Chart Charlie.”