Lilly Walters has a fantastic book entitled “1001 Ways to Make More Money as a Speaker, Consultant, or Trainer”.
In one of the sections, she talks about having a product to sell with your presentations. If you are an author, you already have a product – your book!
Begin designing a program around the subject matter of your book. If it is non-fiction, then you can offer expert advice in that particular field. Even if it is fiction, you can usually find a topic on which to speak. This can eventually lead to another book focused solely on your presentation that can be sold during your speaking engagements.
So get creative – what do you have to offer others?