Do something poorly/dangerous in the gym, attach yourself (politely) to the person who comes to help,
Or do something you're passionate about and offer your knowledge to people who are earnestly trying their best but not doing it well (be conscience and ask if they'd like your experience to guide them)
Alternatively go hang out at an old folks home, they'd love your company, they'll regail you with stories from their glory days, and they'll probably talk you up to their family.
Volunteer your time at animal shelters/public service events.
I hate it as a tactic that's been used on me, but darn if it isn't effective. Also I genuinely appreciate people who offer their advice when I'm doing something foolishly, but my actions are from a place of genuine ignorance, not trying to catch someone into my friend circle.