Having a call to Action in a presentation doesn't mean having a slide with some links for more information. It's about having a single action that the audience listening should do next.
Your job as a speaker is to, over the course of the presentation, take the audience on a journey from their current position to an end position that you have defined and then take action.
If your presentation is about new technology, your call to action should be a single, easy to understand next step. It might be signing up for a trial, registering for a training event or agreeing to chat to you one to one.
Whatever it is, it should be a definite offer, and ideally something you can track.
When you have defined your call to action, be honest with yourself: can you realistically (in the time allocated) take the audience on the journey to your call to action.
If the answer is no, then change the call to action. A call to action doesn't have to be a conversion to a sale. It could be softer than that.
If I know an audience is very far away from being my customer my call to action is often a request for feedback.
Sometimes this will lead to new business, but it always leads to insight.
Do you have opinions on what calls to action should be? Let me know in the comments.