Blogger provides variety of templates that you can use. You can change your templates easily. But if you want to give unique look to your blog, adding custom image as your header is one of the best ways. Header is one of the entity that catches user eye. So if it is unique, entire blog seems to be unique. A bit tweaking of other part of blog will give rise to complete unique look.
So let us jot down the steps about how to add unique header to your blog....
Step 1: Create a image of proper size. (How to adjust width of blogger blog?)
Step 2: Go to blogger layout section. You will see the following image.
Step 3: Click Edit. And then choose the correct file from link below.
Step 4 : Choose the desired image from your computer. You may also put the URL of the image. Choose the Placement Option and click save.
Still have doubts. See the screen cast below.