1.) Get your 'ingredients together' - pick your notebook and whatever you are going to make your pocket out of. In this case, I raided my charity shop book stash on my collage shelf and went for a cupcake piccie. You could use craft card for this as well. I wouldn't recommend paper from a magazine or comic as it might be too thin to stand up to regular handling. Grab a roll of washi tape or cellotape, and a roll of double-sided sticky tape.
2.) Cut paper to size so it won't stick out of your notebook when done.
3.) Fold the pocket piece in half.
4.) Cut two pieces of paper/ card for the gussets on the sides of the pocket - i.e. the pieces that will give the pocket depth. I used two bits from the offcut of the original picture but you could use whatever - again, pick something durable rather than something lightweight. I would recommend cutting a piece that is at least 2 inches wide, and about an inch shorter in length than the folded pocket panel.
5.) Fold both pieces.
6.) Fold over each side again, but smaller folds this time.
7.) Place one of the folded pieces on one side of your pocket. This is how it should look, the V of the paper pointing down.
8.) Using washi tape or cellotape (washi tape is a more decorative finish) stick down the folded flap that is hooked over the front of the pocket.
9.) Turn the pocket over and, using the double sided tape, stick the other folded flap down.
10.) Repeat the above couple of steps with the other folded piece of paper/ card.
11.) Add two more strips of double sided tape to the back of the pocket.
12.) Peel the top off the double sided tape and stick on to the back cover of the notepad.
And voila! A handy pocket for postcards, notes, vouchers, receipts - whatever scraps of paper you deem worthy of keeping.