What are the best ways to find someone?

[Veronica Alicia]

You don't say which Country; I can only answer for the UK, although a couple of US sites are http://www.411.com for phone numbers and full addresses, and Zabasearch which I haven't used.
UK - Friends reunited is now a free site - he may be a registered user. Also Facebook.
phone numbers and full addresses if he has a land line http://www.192.com (I prefer the bt one)
You could try someone who has a copy of the Electoral Roll "plumbed" into their computer so long as you don't ask for a John Smith in London! The INFO disc as it is called is 80% complete. I know someone who has and makes no charge - I can't advise you any more about that since it is unethical to publish someone's personal details here and you don't allow e-mail.
Vehicle Registration won't give you details of car owners - sorry.
You could try a letter to the person's local newspaper - address it to "The Readers' Letters Column" and ask if anyone knows how to contact John Smith.