You will need a 15cm square piece of paper (plain or patterned), washi tape and scissors
Face your paper pointing like a diamond
Fold in half - make sure you make nice crisp creases on all your folds
Fold up the right quarter to meet the top point
And do the same on the other side
Unfold the last two steps and fold down the top point to meet the middle
Fold up the right side again
Tuck the point underneath to start forming a pocket
Do the same on the other side
Now you just need to decorate with washi tape and happy reading!