1.Log in to your blogger account.
2.From your dashboard click layout and go to edit html.
3.Find this line /*----Sidebar-----*/
4.And paste the code below
But before that you have to look the widget id name of your blog list or one particular widget in your sidebar.
<b:widget id='BlogList1' locked='false' title='Friendly Bloggers' type='BlogList'/>
The highlighted red is the widget id name.
So change the highlighted blue into highlighted red.
It should come out like this.
You can change the height whenever you want it to be.
As simple as that.The finish of this tutorial is in my sidebar widget Friendly Bloggers.Enjoy!!!