blog theme

You need the programming skills for this urpose...

To create a blog template, you first have an idea or image that is created. Once you get the idea, you will need a graphics editor like Photoshop or Paint GIMP for pictures in the background, headers, message boxes, etc. Then work on the CSS (Cascading.Style.Sheets). If you can not use it, you can apply interesting effects to your new design model such as images or text placement, establishing funds repeated, moving images and text, etc. Then set up and reconstituted in HTML.

By making a theme, u need to know not only design but also code...
I suggest u to choose a free template, there are hundreds of thousands templates available.

you can create a blogger online theme it is bets thing to do

It needs php expertise to create site design. But there are a large number of design that you can change and create yours.

you can chose it according to their need