Notebook mine was approximately A5 sixe.
Fabric cotton, linen, polyester velvet, polyester taffeta, all work well.
Water soluble fabric or acetate lining fabric.
Wide Bias binding and cord to create bias corded insert if wished.
Cutting mat and roller cutter.
1. Measure around the notebook,from edge of back cover to edge of front cover, and the height of the notebook.
2. Decide how many panels the cover should have and their measurements. I usually make a drawing at this point. Add seam allowances, 1cm for side seams but 2 cms each for top edge and bottom edge.
This the drawing and the measurements I use for the red and navy spot notebook cover.
Increase the measurement of rectangles to be textured by the % of shrinkage
Front panels in hoop
4. Lay the stitched panels on a cutting mat in the correct order.
5.With a roller cutter cut the textured panels to the exact sixe required.
6. Line the panels up again to check. Cut two rectangular pieces of fabric to act as the pockets to hold the notebook in. In photo they are placed to the right and left of the cover pieces.
7. The panels are now ready to sew together inserting and decorative bias cord into the seams if wished. If any ties to keep the notebook closed are wanted add now.
8. Check the fit of the cover around the notebook and adjust as necessary. Hem one long side of each pocket piece and then with right sides together seam to along the other other 3 edges.
9.Turn right sides out, fold in top and bottom hems and top stitch all around the edge of the cover.
As this was just for my own use I did not line it but if giving as a gift then I add a lining.
Playing further here is another bag.