How do you upgrade to first class?

I only fly 3-4x per year, so maybe I can’t, but how do people upgrade to first class (I generally fly American) without paying for a first class ticket upfront? Be gentle with me, I’m new to this. --- **Post Details:** - **Subreddit:** r/travelhacks - **Author:** u/Garden-Girl-Jones - **Score:** 35 upvotes - **Upvote Ratio:** 73.0% - **Comments:** 76 - **Posted:** 6/28/2025 - **URL:** https://reddit.com/r/TravelHacks/comments/1lmnhh2/how_do_you_upgrade_to_first_class/