I have about 30 pages on my site created entirely for SEO purposes.
Fifteen of them are built around the math curriculum. They start with Preschool math and are crammed with words like preschool math lesson plans, printable worksheets, and curriculum. They continue up to eighth grade math which is full of ....yes....eighth grade math lesson plans, printable worksheets, and curriculum. While these do not read or flow as well as I would like, they have been effective at drawing traffic.
Fifteen more of them are built around a carefully constructed set of keyphrases chosen thru a tight methodology which picked the best keyphrases balancing where my site is competitive enough to get on the first page and the volum is high enough to merit the effort. These have been so far a bust (although other parts of the methodology such as building the page template have contributed to the math pages success).
Next in line, a chunk of pages by grade on spelling and reading.
I keep track of it all on my reading, writing, math, spelling page