You can mark me down for this job, I've had it since the 70's and still going strong. Friends, co-workers, and friends of friends I don't even know email the ages of their kids and I will photoshop maps of what attractions I would take them on and what routes I would take to get there.
The first thing I tell them to do (if they have kids) is to buy Birnbaum's WDW For Kids book, read it to their kids at night and let them mark it up with comments. Then when I get that report maps are neatly sent via email and I request a "trip report" upon their return as payment.
I enjoy being the live tour guide most. Our next trip is the first full week of December at which time there'll be 22 of us going. 12 of them will be first-timers and I can't wait to see the smiles on their faces as we enjoy our vacation.
A friend of mine in Vancouver went down on my advice with his two daughters (4/6) last year and I enjoy hearing his stories of how they still make him play the abominable snowman for EE when he gets home from work. He enjoyed it so much he is flying down to meet us in December to get the "first-hand" experience, lol...