Most public speaking books will tell you to be a polished speaker you have to tie all your information together so it flows smoothly. You must lead your audience and alert them that slightly different, but related information is coming. This is called transition or segue (pronounced seg-way).
LET ME STATE RIGHT NOW THAT I FULLY BELIEVE SMOOTH TRANSITIONS ARE A NECESSITY IF YOU WANT TO HAVE YOUR AUDIENCE MEMBERS SO BORED THEY FALL RIGHT OUT OF THEIR SEATS AND SMASH THEIR HEADS ON THE FLOOR.
Come with me to the amusement park. Look around a little bit and tell me where the excitement is. Of course, it's over on the roller coaster where transitions are sharp. They are sharp and exciting even though you can see them coming. The excitement isn't over at the kiddie choo choo train (notwithstanding, the excitement you might feel watching your little munchkin on there for the very first time) where turns and motion are mild so the little ones don't get too upset. The excitement is also at the bumper cars where you can get blind-sided because cars are coming at you from all directions. The excitement isn't at the baby boat ride where a 2cm wave would flip your little bundle of joy out of the boat.
OK. when speaking in public I'll admit, some thought should be given to transition, especially with older, more traditional audiences, and when you have a very high content presentation. But you don't have to be a trite, snoozer by saying things like, . . . speaking of bananas. I'm now going to talk about bananas. You could, however, do a segue like that and then make fun of yourself for doing it by saying something like, Don't you think that transition was really smooth? Transitions are one of the places where you could plan to use some humor. This works well with technical audiences because they won't feel you are wasting their time. Since, in their minds, you are REQUIRED to do a transition anyway, it's OK if it's funny.
Segues aren't important at all for 85 percent or higher humor content presenters or stand-up comics. You can just speak away and as long as they are laughing, no one much cares about transitions. If you are not in this category, then you can begin paying a little attention to bridging the gaps between your points and topics. Just don't be trite and don't think you have to say something to make the transition.
You can make transitions by changing stage position, pausing, using visual aids, giving out a handout, picking up a prop or sharply varying the sound you make come out of the public address system. Do anything that breaks the pattern of what you were doing in the previous segment and introduces what you plan to do.
For verbal transitions, one-liners, anecdotes, and questions work well. Also, people seem to like and need recaps, so I am in favor of saying things like, To recap this section . . .
When speaking in public, whatever you do, think in terms of roller coasters and bumper cars so you keep your audience excited and alert all the time.