You can find the original post here : http://www.instructables.com/id/Hungarian-Shelves/
In this post I just want to share my experience in making them and show the slight differences I introduced.
Step 1: Prepare the job
For your own project, take accurate dimensions and use sketches to find out approximately how much material you will need to buy. I actually made a basic CAD model so I could figure out better how it would look, and this helped me later for dimensions and to estimate the amount of paint I would need.
Don't underestimate this step and plan your work carefully if you want something nice at the end. I went to the shops to find out what dimensions of wood were available and at what price before I made my decision on the final design.