Meta-advice: When reading advice collection posts such as this one, find the first one that really resonates with you, then stop reading. The brain can't absorb several life-changing concepts within a few minutes of another. After stopping and thinking deeply about one bit of advice and ideally doing something else for a while, you can come back if you want.
alternative: copy-paste the ones that speak to you into a document or something, and the review it every few years.
i've got an internal, personal 'wikiquote' doc of stuff that I like, and i make a point to review it, add to it, and meditate on its contents periodically.
