1. LinkedIn: search by school and year
LinkedIn is by far your most powerful tool. Don't just search by name (people may have married or changed their name) — use the "Education" section. Go to your old school's company page and click "Alumni". There you can filter by graduation year.
2. The snowball effect
Once you've found one person, immediately ask: "Who do you still keep in touch with from back then?" Almost everyone is still in contact with at least two or three others. Before you know it, you have a tree structure covering the whole class.
3. The school alumni list
Call the admin office of your old school. Some schools have an alumni association or keep lists for reunion purposes. Due to privacy rules they often can't give you the list directly, but they may be able to forward an invitation to their database on your behalf.
4. Play family detective
Can't find someone at all? Search for the surname in the area they grew up in. Parents often still live at the same address or in the same town. A polite message on Facebook to a sibling can also work wonders.
5. Create a WhatsApp group (selectively)
A WhatsApp group is handy for the core organising team, but can be overwhelming for a whole class. It's better to use a platform like Mijn Reünie to centralise registrations. The registration page link is very easy to share in any WhatsApp group.
6. The local newspaper
It sounds old-fashioned, but for reunions 25 years or more after the fact, a small notice in the local paper (including the online version) often works very well. Many people still live in the area, or their parents still read the paper.
7. Use the guest list on your website
On Mijn Reünieyou can make the guest list visible to invitees. When people see who's already on the list, they get excited and start messaging others they notice are missing.
Patience is a virtue
Finding 100% of the class almost never happens, but with 70–80% you already have a fantastic reunion. Start early — tracking people down is usually the most time-consuming part of the whole process.