A long deck usually becomes shorter through prioritization, not smaller fonts. The goal is to protect the argument while removing content that does not change what the audience understands or decides.
Write the core message first
Summarize the presentation in one sentence and list the few points required to support it. Slides outside that chain are the first candidates for removal or backup.
Combine slides that make the same point
Three slides with similar charts, examples, or arguments can often become one stronger slide. Keep the clearest evidence and remove repetition.
Move useful detail to backup
Technical explanations, methodology, alternative scenarios, and detailed tables may still be valuable. Move them to an appendix rather than deleting information the audience might need during questions.
Use AI to identify redundancy
An AI presentation workflow can help summarize sections and flag repeated ideas. Use that as a review aid, then decide manually which evidence is essential to the audience.
Check the shortened deck against the decision
After cutting, ask whether the audience still has enough context, evidence, and clarity to reach the intended conclusion. If yes, the removed material was probably not part of the core story.