It very much depends on what you are doing, and how you like to present. Each effect has a different presentation, yet my show, has an overall 'story' that I am telling that I tell during the transitions and using the effects.
I look at what is happening in the effect and I try to think of what that might be an analogy for. Then I weave a presentation around that.
For example, my version of the
Biddle Trick, starts off with me asking if anyone has ever seen the movie 'Maverick'. (Less and less people say yes to that now!- I'm getting old). There are always people who haven't seen it, so I explain that it had Mel Gibbson and Jodi Foster, and Mel Gibbson played a river boat gambler. And there is a scene in the movie where his dad tells him that if he closes his eyes and thinks hard enough about a single card, he should be able to cut straight to the card he was thinking of. And the trick plays out where I just can't get it, and eventually they try and cut right to their own card. (If you want to see
my old presentation, here you go.). My presentation has changed since that video. Now I cut the deck with no luck, and use the excuse to use less cards, then I take 5 cards and continue to fail. Then I have them try with their deck and they cur right to their face up card in the deck. So cutting the deck becomes the theme of the story, and they become the 'hero'.