I created unity throughout the calendar by using the same paper set on all the pages. I also used 3 squares - a photo, a calendar and a space for notes - on each page. (except one).
I didn't want every page to be the same though, so I varied the design of each page by sketching out the designs ahead of time. Finally, I added a sticker sentiment and some twine and/or ribbon to each page.
The base of each page is just plain cardstock so that it was easy to place the finished pages into my Bind it All and punch the holes for the bindings.