I promise this was mostly not a procrastination activity. Oxfam usually sell the diaries I like: month to view, small pages, thick card, Sundays the same size as all the other days. This year they have STOPPED. So I decided to make one myself.
Step one: make a document with your calendar in it, print all pages and crop.
Fold pages carefully. At this point I realised I had laid it out all wrong. Half of January should have been December, every month should be split, and then I could have stapled the whole thing. Instead I decided I would have to sew it together.
Gather pages carefully; I have now added an oscillating page aligner to my imaginary birthday list – I’m sure one exists.
Clamp.
Sew into the spine of each page and then up and over the top of it, them cross from one page to the next. I wish I hadn’t folded the pages so sharply, it was much harder to get the needle into the right place. 
Re-clamp and repeat at the other end, and again in the middle.
Attach a ribbon onto the back page.
Glue or tape the spines, and the first and last pages, to the cover. I didn’t glue the spines at first and all the middle pages were moving about.
Et voila!
(Harry Potter says “Expecto Patronus” and my diary appears. It’s magic.)