Free Online Graph Paper

Here's another resource link I've found very useful http://incompetech.com/graphpaper/lite/. You can start of with really big squares and then gradually make them smaller.  That way you can get your proportions right before you work on writing it in a smaller size. Just change the numbers and print out a couple of different ones until you find your match. Or try any of the A4 pdfs I'm using, Get-it-right-generous-size sheet (14x20) or Route-learning-size sheet (20x30).