When targetting
the Long Tail of search, you not only try to find less competitive targeted phrases, you
structure,
write and
interlink your content in such a way that your pages are associated with a variety of related relevant keywords.
In general, it means writing plenty of content, using synonyms, derivatives (stemmings), getting linked to with a variety of anchor texts (preferrably naturally), etc.
In a way, targetting the Long Tail of search is easier than targetting the competitive phrases. You don't simply target keyphrases like you used to, but you target the way the searchers will find your website.
Of course, you need to remember your main keyphrases to actually attempt to get lots of targeted traffic in the long run.
By the way, if you only target the long tail, you won't get much without using competitive keyphrases there and keyword research. As Chris said in
his book, if you target only the Long Tail, you will lose, because you will have no focus, no specific theme. I'll add that you won't have a niche there, which may be easier understandable here.