I have a suggestion for this specific article. I like that it's short and sweet, but I think it could have used a mention of the C-x e e e e e e pattern. I find myself using this all the time to do medium difficulty refactoring on a section of code. Rarely, if ever, do I use C-u 0 C-x e.

Something on code navigation & smart code completion.

I am going to echo a reply elsewhere on this thread and say you should contribute to the emacswiki if you can as well.