I agree that one needs to do those basics, which are fairly well known. But I'm afraid that's "old world" thinking. There is absolutely NO stability, or predictability about how search engines, particularly google, index pages.
That's THE obvious lesson that many aren't quite getting. Someone can do all the basics on a new site, or modified site, have the best darned site on its topic, have good inbound links, and get absolutely nowhere. You can fiddle, tweak, listen to "experts" who really don't know what's going on (since nobody does), and end up with a large investment of time, horrible rankings, and no income.
Or, you could hit the jackpot. It's like playing slot machines now, and for people who are into that, that's fine. But trying to run a business that is completely (and I mean completely) unpredictable is not a wise choice for many people.
Stability and a somewhat predictable business environment is one of, if not the most important requirements to run a successful business long term. Right now we don't have it.
Speaking for us, until we have some stability, we're not investing much in web development beyond basic maintenance tasks. We aren't redesigning our sites (that too is a crap shoot - if we redesign do we lose whatever rankings we have left?) We aren't investing ad money, either, into adwords, and we aren't counting on adsense revenues. We'll be ready if things improve, but we're moving our business elsewhere, so to speak.
I'm through playing guessing games with google.