Match the pacing to a much shorter attention span
A video made for YouTube or a podcast typically opens slowly, building context before getting to the point. A Reel cut from the same source usually needs to start at or near the actual payoff, with the slower build-up trimmed away entirely, not just shortened.
Pull a carousel from a written piece
A blog post or long caption with a clear structure (steps, a list, a few distinct points) often converts well into a carousel, with each slide covering one point. It works especially well for content useful as a reference, since a carousel is built for saving and revisiting.
Re-shoot the intro rather than trimming an existing one
The first few seconds of a Reel do a different job than the opening of a longer video: earning an immediate stop rather than building context. It is often faster to record a short new intro for the repurposed clip than to hunt for a usable moment inside the original file.