Keep it short,less the better
Must mention the Bride also, What a wonderful person,blah,blah,blah.
Her old man is footing the bill,keep him happy.
Take a shot at the Groom ,keep it clean,etc.
Jokes should be something that most in the crowd are familiar with
If it regards the Groom
Tell everyone in the audience that has a key to the grooms house, that they must now return it. Have about 10 hot girls come and drop a key in front of you and then one fat ass, hairy guy do the same..
I did it twice...
Never talk about the past GF or Night Outs getting drunk.
Always write your speech down on paper and have it in front of you (just in case you freeze or forget something)
Start with humor, end with sentiment. Don't get crude. Speak glowingly of how the groom flipped for the bride and how she got herself a great guy. You're not doing stand-up, so err to the classy side. Do not go too long.