One hundred words to the minute. Write the entire speech out verbatim. Stand up (in a quiet room) and read it out aloud. Change all those words you trip up on. Read it again. Amend it again.
You can tell jokes? No problem.
You can't? Then don't.
A casual aside can work far better even if it is one that potentially embarassed you at the time.
prattle prattle prattle dying for a cuppa and this mate starred. Brought me a cup of hot tea just in time. Then this conker dropped in it. Went everywhere. .............. at least it warmed me up. prattle prattle prattle