- Social Media: Regardless of age people are flocking to social media to stay in touch with far-flung relations. Don't restrict your search to just the person you seek. If you know of any relations, spouse, children, etc. try them all!
- Telephone Listings: Canada 411, if they have a publically listed phone number it'll be here. There is also an option to do a reverse address search. Some phone providers (like Telus) also offer their own phone listings that may not be available on Canada 411.
If presumed deceased...
- Death Records: Are only available to next-of-kin or a legal representative until 72 years have passed. After 72 years death registrations are released to Archives of Ontario and can be publically viewed.
- Cemetery Records: Search OCFA, OGS, CanadaGenWeb's Cemetery Project and other websites that offer Ontario cemetery recordings.
- Obituaries: Obituary Daily Times offers an index of some Ontario obituaries, mostly from the past decade. If you know the last known residence of the person you're seeking check local newspapers, many Ontario newspapers now offer an online index of obituaries from 2002 onward.
If you are unable to locate the person in question broaden your search to include their family. A parent, sibling, or child's obituary might yield new clues. Don't forget to browse some online trees to see if someone else is researching the same family.