Next time when you do a pitch in a 1-on-1 meeting record the audio (obviously ask your meeting guest). Back in the office, play it back with the slide presentation closed. Hit pause after every major point and scribble/sketch a quick chart you would use to make that point. When finished, compare your scribble with your slide deck and make the required changes.
Image on WikiPedia
SlideMagic: a platform for magical presentations. Free student plan available.