I've got 816 photos approved and published on it so far, and have gotten some nice sales from it over the years.
Will you share what kind of pictures and how you got the sales?
The ones that are approved are landscapes, cityscapes, bridges, buildings, street scenes, etc., per the rules of what's acceptable for approval. Photos where the subject is a vehicle, person, animal or other object that is not likely to be at that location if someone were to go there to look at are generally not approved for Google Earth, though I have quite a few of those up in my portfolio as well; Mostly from my early days using it and not knowing exactly where to draw that line.
Sometimes their decisions on what to approve don't seem to make sense. I've submitted appeals for a re-evaluation from time to time, and sometimes they end up approving, and sometimes not. It is what it is.
As for sales, people see them on Google Earth or on search engines or other means via Google Earth, my contact info is available through that, and those interested then contact me to use them for various purposes; advertising, calendars, book jackets, CD covers, web sites, prints, posters, etc.
My photos are viewed typically between 4000 and 6000 times per day. My most popular photos are seen some 400 times per day each. All told, I get about 150,000 photo views per month, and since I started uploading photos to it in 2007, they've been viewed over 7 million times. And it's never cost me a dime. Can't beat the price of that advertising vehicle.
Here's a link to my Panoramio portfolio to give you a better idea what I put up there, and what gets approved (little blue compass dot means approved):
Panoramio - Photos by Buck Cash