This pencil case doesn't require a lot of sewing skills (in fact, I made this one with my toddler sitting on my lap), and it is endlessly customizable. Pick patterned felt or ribbon, various color combinations, or paint it with fabric paints before you sew it.
Fold your felt vertically, bringing the bottom edge about two inches from the top edge (so it should now measure 9 inches across and about 7 inches up). Pin, if necessary, and sew along the right and left edges.
Sew pockets for your pencils by stitching a straight line from the bottom to the top of the folded part (to fit a #2 pencil, I made my seams half an inch apart). Make sure to backstitch at the top and bottom to keep them from tearing with use. You can sew pockets along the entire piece of felt or you can leave half of it unstitched (like I did) to make room for a little notepad or sticky notes.
Turn your pencil case over so the back is facing up and pin the center of the ribbon along the stitched line closest to the center. Sew the ribbon to that line and remove pin. Fill your case up with pencils, roll it shut and tie closed with the ribbon!