Take a look at your slides. For each slide, think how you would present the same information if you didn’t have the slide. Practise that, so that you can give the information on the slide without using the slide as an aide memoire. Practise that, until you can introduce that topic, discuss it, and move on to the next without a single reference to the slide. Do the same for each slide.
How will that improve my slides?
It won’t. It will improve your presentation with slides, by turning it into a presentation without slides.
As an optional extra, you could make new slides that support the presentation, but it shouldn’t be necessary.