Using smart links plugin search in google ''smart link''. This plugin interlink all your articles together in your website.

Use them to link to other article and other pages in your site when the keywords pop up. Don't stuff it with too many though. I would say max 1 link to every 200 words.

On Drupal I use the module "similar by terms" which allows me to put blocks around the content. The goal is not for google, but to prompt visitors to explore other similar content within the site, so they stay more and get more out of their visit. That's why I put the block (short version) at the top, before the content itself, and then another one (more complete, with teaser) after the content.

Don't post many outbound links too, you are giving page rank to other pages.

I hope this link would be helpful to you;

Two Awesome SEO Wordpress Plugins For Internal Links