There are loads of videos on YouTube and example speeches on the Internet. Divulge these then remember to not use ANY of their material. Witnessed so many speeches with lazy unoriginal re-hashed jokes…
Visual gags are good tho. When I did it the groom was an electrician, I joked that we were only in this room because he re wired the place so got it cheap,, I had ushers on standby to make a loud bang through the speakers and turn all the lights out on cue! Went down a treat!