I found this great tutorial on-line showing you how to make an altered notepad. I got this info from the website StarLit Studio. It is a great gift for teachers, moms, sisters, or friends.
It has a template that you can print off and it shows you the exact sizes to cut the paper. It uses a double sided 12 x 12 paper and a 5 x 8 notepad.
Here are some samples of the notepads that my mother and I put together. We cut some of the notepads in half and made covers for them. We also made a couple of super mini sized ones. My husband has a heavy duty paper cutter that cuts 100 sheets at a time. If you would like to trim your notebooks you could also take somewhere like Office Max and have them cut them for you.