Slow down: Always pause and think before you speak
Consider anything you share with someone who hasn't earned your complete trust or whom you have a transactional relationship with to be a PSA; Don't trust anything to be confidential with someone you don't fully trust
Reflect on why you overshare in the first place: Do you use it as a tool to soothe social anxiety or pauses in a conversation? Are you lonely or feel like it's a struggle to feel heard/seen/appreciated in your everyday life? Start journaling and/or go to a therapist to work through these very valid emotional wounds
Give yourself a "do's" and "don'ts" list on topics you will and won't discuss at work, different social events, with certain acquaintances, family members, etc., and stick to it
When you feel yourself starting to overshare, take a pause and ask the other person about themselves – it makes you show the other person you're interested in connecting and gives you time to think/reflect on what you should or shouldn't say