Path Names

Make Folder, Subdomain Name, and Page Names Match Content

For example:

http://www.united-way.org/good-samaritan-awards/repeat-winners/joe-smith.html

http://www.littleton-police-dept.gov/criminal-records/career-criminals/violent-offenders/joe-smith.html

Humans categorize Joe Smith very differently based on folder path. So do search engines.

Create "Semantic" URLs that convey information:

Good:
http://www.karlkelman.com/skiing/arapahoe-basin/pali-ski-trail/powder-day.html

Bad:
http://www.karlkelman.com/big-folder-1a/photo-stuff/trail-43/page-12.html

Assume Bots Read All Your Code:

Compass

For the two pages above, you might use a graphic with "Karl Kelman" at the top of the page. If the page is about Karl Kelman and skiing, a good path for the graphic element might be:

http://www.karlkelman.com/art/ski-page-graphics/karl-kelman-logo.gif

And use an Alt Tag for the graphic element: "Karl Kelman"

Don't try to spam the bots with alt tag... ...that's something search engine technology can detect occasionally now, and they'll get better and better at it.