Use what you actually shared
A school, club or former workplace can distinguish common names better than a face resemblance. Start with public alumni or community channels that allow contact. Ask a mutual acquaintance to pass along your message rather than disclose the person’s private contact details.
Make the first message easy to decline
Say who you are, mention the shared context and explain why you are reaching out. Avoid including private history in a public comment. One brief message is usually more respectful than contacting multiple accounts repeatedly.
Allow for mistaken identity
A reused username, old photo or similar name may belong to someone else. Ask a neutral question about the shared context rather than claiming you have identified them. Do not use private addresses or relatives to force a connection.
Respect silence
People change names, leave platforms and choose not to reconnect. An unanswered message is not a search problem you need to solve. Read the people-search overview for a context-first approach and the username guide for common sources of confusion.