Write a summary slide for each section of your talk, even if you don't use it.
You should probably use an outline slide in your presentation and return to the outline after each section of your talk.
I recommend creating a summary slide at the end of each section and before you return to the outline slide. This slide should recap the points the audience should have learned from the slides in that section.
You may ultimately choose not to use the section summary slides in your oral presentation. They may make the presentation too repetitive and pedantic. Still the process of making the summary slide will force you to consider whether the audience has learned what you want them to learn. Perhaps more importantly, it will force you to think though what you want the audience to learn!