When first time i installed Related post plugin, it showed no related post on any of my post. I dont know exectly what was the problem with that plugin. This may be due to i am not using tag for my posts by tag warrior or any other plugins.
After trying lot and searching google a lot time i found Similar Post Plugin, i installed it and and after putting code in my CSS file, the code start giving result for each post. In tis way i need not to worry about keyword or taggs for my blog. you can customize it in various ways.
Here is some key point you must to see related post in each post.
1. Install Similar Post Plugin
2. Go to option> similar post option > adjust your setting or you can use default value,
3. Go to Presentation > Edit Widget> Single Post.php
4 Put the one line line code given on instruction to above that code which is related to comment
5. Save the file and see the result.