This is my process to make a sketchbook with simple materials and tools you may certainly have at home. A nice feature of this notebook is that it can lay flat on a table and its covers are wrapped in cloth.
Step 1: Folding and Cutting
Gather coloured sheets of paper (A4 size) and fold once. When pressing, use a blunt object, e.g. a fork, to obtain neat folded edges. I have folded 4 sets or sections of A4 sheets (each set has 4 folded sheets). When you have folded all sets, cut in half using a knife. The final sketchbook will be approximately 10cm x 14cm (almost A6 size, 4×6in), after trimming the edges.
Step 2: Making the Holes
Using a pushpin, puncture the inner side of the folded sets. There should be an even number of holes. In this case, given the size of the notebook, there will be four holes.
Use one inner sheet with four holes as a template to finish the other sets. You will get aligned holes.
Step 3: Sewing
When all holes are ready, grab the first set of folded sheets and start sewing into the inside of the sets. Start from any hole that is near the edge. Use a regular sewing thread. Join the sections together at both ends with knots.
Step 4: Gluing
Once all the sets are sewn, we need to glue a piece of cloth. This will keep the sections fastened together, specially when the book is opened between the sets.
Find a regular piece of cloth, from a discarded shirt for example. It should cover the back of the sections and extend around 1.5cm (0.6in) around the first and last page (Please see last photo of the set).
Apply adhesive to the back of the sets and half an inch on the first and last page of the notebook, then attach the piece of cloth. Finally make sure the piece is glued to the sheet and trim any excess.
Step 5: Trimming the Edges
After waiting for the glue to harden, you can now trim the edges with a utility knife. First, sharp the blade by removing one section.
For an even result, you have to make several passes or cuts, not pressing hard and keeping a steady pulse. Try to maintain the blade at a 90° angle when cutting.
Step 6: Covers: Cardboard
Get a cardboard and cut three pieces as shown in the pictures. The two main pieces for the covers extend 5m (.2in) from the inner section, so measure accordingly. The third smaller piece of cardboard for the back of the notebook is as thick as the other pieces together.
Step 7: Covers: Layout
Place three pieces of cardboard as shown in the pictures, with a separation of 5m (.2in) between them. With masking or paper tape hold them in position. You can make sure that it looks all well by attaching the sections before gluing.
Step 8: Covers: Gluing the Lining
The lining or cover is made of cotton (an old T-shirt). Cut a piece that extends around 1cm (.4in) outside the cardboard pieces and apply glue. Once it is glued, turn it and apply glue to the edges and fold the cloth.
Step 9: Gluing the Covers
Now that the covers are lined, we have to attach it to the sections.
First get a thick sheet of paper, fold it and cut it to the size of the sections. This folded sheet will keep the sections attached to the covers. It is not glued at the back, but only in the inner edges. When the notebook is open, the back of the cover separates or departs from the back of the sections, so they have to move freely. You can see this illustrated in the last picture of this set of photos.
Make sure that the sets of folded sheets is just right in the center compared to the covers. I used a piece of masking tape to mark this, before gluing.
Step 10: Result
This is how the final notebook looks like. You can see in the pictures that it actually lays flat when open.