If there are some pages that need not be searched in search engines , then you must not waste your time to pagerank those pages. One must place a nofollow tag in the links to the websites that you do not trust. . I can say that i don't like the time spent and that's why i hired someone. But before that here is what i have manage to learn:The code that is placed must be valid as bad code can lead search engines for not reading the page.
SEO Tips and Strategy:-
Ethic way
Black hat techniques
Use of Link Farms and IBLNs
One must use header tags wherever it is possible and this requires some CSS usage