A common mistake or misconception with web site owners is that the home page / base URL has to be the one listed in the search engine results for any given keyword.

The problem with this is that, once you start to hit 10-20 keywords your efforts can become diluted and you end up cramming too much information onto the page.

You should optimise your deeper pages for relevant keywords and phrases so that they also appear in the SERPS.

One good way to do this is internal linking. For every keyword, if you can, place some content on every page (not duplicate content, make it different) and have that point to the page dedicated to that topic. Then work on external links pointing to the deep pages also.

The beauty of this is also that when someone types in the keyword that you have optimised the page for they are being shown the direct page that is relevant to them, and they don't have to click through your sites navigation structure to find it.