Recently I started improving inner linking of my blog. That means I link to related post from my archive in every new post I made. I don't use related post plugin, I just add link if I see useful keyword in my post.
For example:
I have written something about link building and I mentioned article marketing in it. I have written post about article marketing before and I just add link on anchor text 'article marketing'.
Example:
I can see the improvement in my SERP and more traffic from SE.