How can you verify a blog I will show you how I did it.

Verification of the blog is very important because google needs to know that you are the site owner before they show any your site's results, and  verification does not affect PageRank or affect your site's performance.
how to verify a blog?
Verification by Google Webmaster Tools 

 Sign up for Google Webmaster Tools and if you did not,add your site there.
After you added your site  click on your site after that you will see on the right site little wheel, click on it and chose Verify this site.
In the Verification method you have a drop-down list to chose what type verification you want,if you want you can  select (HTML) Meta tag .
Copy the code that appears and add it to your site,when you paste it in your site,then come back and click 'verify'
You have also other mothods like verification by Google Analytics, it's also easy just follow all steps.

 That's it :)