Essential keywords: do your own digging
MarketingSherpa: Special Report: Online Keyword Research Guide: 5 Tips & 9 Useful Tools notes that:
“A solid keyword list is the foundation of a successful search-marketing strategy. Marketers must continually work to find relevant search terms and understand the volume of traffic they provide — as well as the number of competitors using the same [...]


Angela Booth, top copywriter, author and writing teacher.
Writers Ezine, Packed with Writing Tips
Info Product Maestro: Make $500 a Day with Your Information Products