The most important thing to remember is there is no secret recipe for doing this. Rather, you need to think about the person you're trying to find an decide which methods apply best. For example, if you want to call someone on the phone, all you really need is a city/state and you can look them up in one of the on-line phone books. Many people are actually listed somewhere on the Internet and don't even know it so using a seach engine (I prefer google) can often find them, but the problem is there may be a lot of people with the same name so you often need to include additional information about where they live, what thier profession is or possibly what hobbies they may be known to have. Below are some of the techniques I've used to find many of the people on this list. If anyone has any of their own favorites, just send them along to me and I'll add them.
For me, the main tool for this is google. If someone ever had anything written about them on the Internet, this will find them. The thing not eveyone realizes is that if you just include a name, such as Mark Seger it will find any pages that contain both names in any order which is probably not what you want. You might even find a page about how to mark your ballot in Florida! If you surround your query in quotes such as "Mark Seger" it will only find pages with those two words together, but in that order too!. To be really complete, you should also search for "Seger Mark" because on some pages you may find names in that order. You can actually look for both in a single query using the word OR in between like this - "Mark Seger" or "Seger Mark" or "Mark J Seger", the third case can be handy if you know someone's middle initial.
In the case of women this can be even more complex since some people use their maiden name as their middle name and still others may include a middle initial. Google has an Advanced Search which I'll just let you read about yourselves.
You can also add other useful information to the search line like company names or towns if you know them, but they goes outside of the quotes, such as "Mark Seger" hp
Finally, if you want to exclude specific information from a search just put a minus sign in front of it such as "Mark Seger" hp -ibm.
A second site that lets you look up birthdays is anybirthday, but the big problem with this one is that it only shows you 5 listings per screen (to get you to pay for the privilege of seeing more names) AND it only shows zip codes. You can look up the zipcode with a search engine like google, but that's a lot more work.
The only downside to this site is you only get the state and not the city. However, you DO get the age and in most cases more than with ussearch. The other thing that I think is really cool with this site is you see a date associated with the information. Sometimes you'll see the same household in mulitple states. That's because they moved and this shows you their history.
If you know the town someone lives in you can always look up their phone number on switchboard. Sometimes, people will actually register their email addresses, which I recommend doing yourself if you want people to be able to find you.
four11 lets you put in a person's name and it will find their email addresses. This is very spotty at best. Often there are too many people with the same name and the city name is often blank.
Using some of these techniques in combinations with each other - get the city someone lives in and use that in a google or four11 search - you just might get lucky and find who you're looking for. Even if you only find the name of a company where someone works, a church they attend or some committee they're a member of, you can send mail to that organization and ask about the person you're looking for.
I have personally sent mail to Schools, Synagogues and Companies and typically start off my message to them with an apology for bothering them if they're the wrong entity to be contacting. Nobody has yelled at me and some have even wished me good luck on my quest.