1.Log in to your dashboard--> layout- -> Edit HTML
2.Click on "Expand Widget Templates"
3.Scroll down to where you see this:

<data:post.body/>
4.Copy one of the code below and paste it immediately after the line <data:post.body/>.
Note : This will add rating widget under your blog post.If you want to add the rating widget under post title, add below code just after <div class='post-header-line-1'/> .
Code 1:
<div style="float:left; margin-right:3px;"></div> <div class="js-kit-rating" expr:path="data:post.url" expr:permalink="data:post.url" expr:title="data:post.title"> </div>
Result:

Code 2:
<div style="float:left; margin-right:3px;"></div> <div class="js-kit-rating" expr:path="data:post.url" expr:permalink="data:post.url" expr:title="data:post.title" view="score"> </div>
Result:

5.Now again scroll down to where you see the </body> tag.
6.Add below code just before the </body> tag.
<script src="http://js-kit.com/ratings.js"></script>
7.Click on "Save Templates" and now you are done.