These are links within your own site to your own pages. Do these links include your most important keywords (keep it natural) for your most important keywords for the url it directs to. How prominent are they? Do your most important urls have links/navigation sitewide? The beginning and end of every page are the most important areas for navigation. If you don't have footer links, try them and see if it helps incorporating your keywords. Also do you have a sitemap. You should, these sitemap links should incorporate naturally your keywords within the link text. Break your sitemap down into categories to group many links into common themes. A site map consisting of many pages can be good. Every url of your site should be included within your sitemap, and every url should be targeting a keyword phrase or more.