Ask how you would ruin your relationships, list it honestly, then compare the list to your actual behavior. The gap is the work.
The idea
In World War II, Charlie Munger was an Air Corps meteorologist. Instead of asking how to keep his pilots safe, he asked how he'd kill them, then steered them away from those conditions. He'd borrowed the move from the mathematician Carl Jacobi: turn a hard problem upside down first. Turns out it works for relationships too. Who knew. "How do I build better relationships?" gets you generic answers. "How would I make sure they fall apart?" gets specific fast, and the answer is personal to your values and tendencies.
How to do it
Write the three things you'd do if you were trying to tank your relationships. Be honest.
Compare the list to how you've actually been showing up lately. Look for the subtle versions: the check-in that's really a warm-up to a favor, the LinkedIn comment written for visibility, the coffee where you talked about yourself for 40 minutes.
Pick one behavior to course-correct this week.
Example
My own list, if I were committed to burning every bridge: only reach out when I need something, open with a compliment that's obviously a setup, make every conversation about me, start pitching within 48 hours of meeting someone, and drop anyone who isn't immediately useful. Do that consistently and your network quietly evaporates, and you probably won't notice until you need someone.
Watch out for
Aim for awareness, since nobody scores perfectly. If you can name the behavior, you can fix it before the damage is done.
Death to Empty Networking: Drop transactional, card-collecting networking, invest in the relationships that matter, and stay good at what you do.
Show You Like Them: Lead with liking ("you matter") over utility ("you're useful to me"); use their name, ask about what they care about, and listen.
Add Value, Don't Just Follow Up: Nobody wants to be followed up with. Treat the follow-up as your cue, and make the touch leave the other person better off.
Generative vs. Transactional Relationships: Transactional relationships end when the exchange does. Generative ones are long-term, uneven and keep creating new value, so they deserve your tracking and care.