Ranking for a competitive keyword is never easy, so before making the link building investment its important to not only target the right keywords, but target the right pages for those keywords. I'd like to discuss some of the ideas one should consider when choosing which page to target for a specific keyword.
First, if you're trying to rank a new site for your chosen keywords, then the situation becomes a lot simpler. Spend the time to plan a site architecture that focuses each page on a particular keyword theme. Doing so will help the search engines classify each page contextually, and keep keyword cannibalization at bay. This image from SEOmoz illustrates the process pretty well:
See? Even this idiot robot knows which page to rank for "snowboards"
It's not always so simple, is it? Old pages outrank newer or better targeted pages, keyword strategy shifts occur, and the competitive landscape changes. Now we have to adapt.
Considering Current SERP Standings
If the page on your site that best matches searcher intent for your keyword is ranked below another page on the site, you've got a bit of a decision to make.
Often this comes up in situations where the home page ranks, but an interior page is really the more targeted page, or vice versa. It can also occur with old pages where organic links have been built up using varied anchor text. Home pages inherently receive more links, so it would probably be easier to rank the home page well for your keyphrase, but sometimes that isn't really the best strategy.
Ranking the Home Page
If your site sells various kinds of snowboards, and only snowboards, the home page is a great page to rank for the "snowboards" keyword. If your site sells snowboard equipment and apparel, including snowboards themselves, then the home page is still a great page to match the "snowboards" query.
Perfectly suitable pages to rank for "snowboards"
But if your site sells all sorts of sporting goods with a dedicated /snowboards/ category, and the home page outranks that category, then it might be best to bite the bullet and begin pushing your proper category page. That means revising your title tags and on-page content and building links to the /snowboards/ page.
Ultimately the category page has the higher potential rank because of super relevant on-page cues, and its probably more likely to convert the searcher into a customer. Additionally, increasing this page's link metrics will allow for greater long-tail search traffic, something that might have suffered on the generalized home page.
Embracing the Random Rankings
Of course, in some instances you'll find that an interior page ranks fairly well for a great keyword that you aren't necessarily targeting.
Let's suppose your happen to rank on the first page for "snowboarding guide", which brings some strong traffic but poor conversions. In order to best take advantage, instead of continuing to target "snowboards" for that page, it would probably be a good idea to switch the focus to match the "guide" modifier, and link to your better-targeted "snowboards" page from the guide.
Nine times out of ten the page that best matches searcher intent is the one that will provide the highest return, especially when it comes to eCommerce sites. Keep a close eye on how users are entering your site, which keywords are leading to the most bounced visits, and where your site ranks. These metrics could lead to some great on-site tweaks that can boost ROI overnight, and provide an idea of which pages should be targeted when link building.