How to determine best keywords

There's a nice little tool - and it's free - from Google that will help you choose.

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Inbound Links that don't contribute to PageRank
Not all Inbound Links are worth something. Know which aren't.

Google PageRank vs. MatchScore
A higher Google PageRank doesn't automatically mean higher in search results.

PageRank doesn't always increase. It can go down too!!
When Inbound Links disappear, it may decrease your own PageRank.

Outbound Links are like Votes
The value of outbound links is divided by the number of them on a given page.

Trustworthy and Relevant.
Google looks for pages that are trustworthy and relevant.