The other week I attended a conference, several speakers followed the following pattern:

A slide pops up, the speaker glimpses at it shortly and starts to talk about it.

He finishes his little speech, the next slide pops up, he glimpses at it shortly and he starts to talk about it.

He finishes his little speech, the next slide pops up ...

Eventually the talk finishes.

Too often presenters focus so much on slides, that it is the slides that dictate the rhythm of the talk.

No matter how well designed the slides are, they should never get in power. They should always be just aids. In fact, they should be those kind of aids that you should do without:

Do not make the talk about the slides, make the slides about the talk.