First of All Make Account on Pinterest and Then Follow Below Steps
Add Pinterest Follow Button in Blogger Blog
Step (1) Go to Blogger.com and Then Go to Your Blog dashboard
Step (2) Go to Layout and then Click on Add Gadgets
Step (3) Now a Popup window will Appears In Title Type Follow me On Pinterest and in Content Paste The Below Code
<a href="http://pinterest.com/TipandTricks/"><img src="http://s-passets-ec.pinimg.com/images/about/buttons/follow-me-on-pinterest-button.png" width="169" height="28" alt="Follow Me on Pinterest" /></a>
Then Replace The Blue Code Link with your Pinterest Link
Step (4) Then Click on Save.
Step (5) Then Click on Save Arrangements
Congrats You are Done Now Go to your Blog and you will See Pinterest Follow Button in your Blog Sidebar.