I'm a newbie and I found this place after a Google, so you're obviously doing something right!
If I can throw a few things in here, which hopefully explain some of the factors behind getting a good ranking if not supplying a load of answers.
Optimising any site for search engines is part science, part art - and sometimes just a little bit of luck thrown in too. The thing to remember is that the main engines - Yahoo! and Google - will rank a site in different ways. Google look at inbound links from other sites deemed to be worthy places themselves. Yahoo uses the older method of page title, META tags and content; these need to tie up so the title has words also featured in the META tags which are also in the content.
Like life however things ain't as simple as the very basic description above. There's a lot of little tricks and practices defined as black or white hat in their methods and tread carefully - the dodgier stuff can earn a 6-month ban from the likes of Google.
Anyway, I'll shut up now! 
Yup, thats right. Getting decent rankings in Yahoo or MS Live search isn't too difficult. Google is the difficult one, as content, and content of links pointing to a site are all part of it. Google frequently modify way PR works, so its a constant battle - a few months ago they knackered some of their own sites, reducing PR from 10 to around 6
