You may never find that formula. It is always changing. I have around 50 sites, several #1 for very competative key phrases. But I also have some sites in the 100s and 200s. I follow pretty much the same rules for all, yet I can't fathom why the differences.
I know, I know... backlinks are different, relational phrases and proximity, ya da ya da yayda are different. Even the sites are completely different. So what works for one does not necessarily work for another.
But it's kind of hard selling that to your clients when it is such a crap shoot. And that is the very first thing I tell them before I start working on their sites.
It's a crap shoot :-)