After the latest google algo update Internal linking has not given much value. Anyway it is a good practice to interlink the inner pages with the content. By internal linking, there could be enough flow of link juice from the home page to the inner pages.

I usually try to include it in my content that has keywords matching the relevancy of the page.

Regards,

thanks for the info

when interlinking my content i make sure to have a list of the keywords i am targeting.
you want to be linking to relevant pages with relevant content and heyword anchor text.
For example:
Your website is selling tshirts--- you have an article about red shirts "Why I love Red Shirts"---- in the article you will want to mention "red shirts"(keyword)----- that should then become your anchor text (<a href="http://www.xyz.com/red-shirts/">red shirts</a>)---- that red shirts anchor text should link to a page about red shirts. Have the page that its linking to have Red Shirts in the title.

Google will see your article is about red shirts, see you are linking to a page on your website using the anchor text "red shirts"(keyword) this will tell google what the page is about, google will then go to that page, see "red shirts" in the title.

hopefully this helps