I have just finished a PDF tutorial for a simple pattern keeper to hold knitting and crocheting patterns. Click the link to open the PDF file.
I recommend frosted vinyl for the pattern keeper. This is easily available from stores like JoAnn Fabrics. I used a page protector for the first one I made. The page protector forms permanent creases. However, you can still see the pattern; and it will work if you can’t find the frosted vinyl.
I hope you enjoy the tutorial!