Show, don't tell. Choose 2 or 3 real, specific moments that genuinely shaped why you want medicine, then spend real space reflecting on what each one taught you rather than just narrating what happened. The AMCAS character limit is 5,300 characters, spaces included, which is tighter than it sounds once you start writing.
Avoid the classic traps: the "grandma got sick" opening with no meaningful follow-up, a resume simply rewritten in paragraph form, or a hero narrative where you single-handedly saved the day. Admissions committees are reading for insight and self-awareness, not drama or a highlight reel. This is genuinely the single area where outside editing from someone who's read hundreds of these tends to make the biggest visible difference, since it's hard to see your own essay's blind spots from the inside.