Last night I sat down and made all of my crackers. I was surprised how easy it was and it only took me about 2 hours to make all 12 (in fact I made 13 but the first one went quite dramatically wrong).
It's a simple process and I basically followed this guide from Kirsty's Homemade Christmas.
I didn't bother to measure anything (I like my crackers to be organic, and I'm lazy) but I regret not using luxury paper as recommended - mine was thin and ripped a bit while I was scrunching it and tying ribbons on.
I got my husband to pick 12 jokes form the internet (we'll see how funny these are soon) and added these, with the gifts. I find places like Hawkins Bazaar (a sort of toy and joke shop), craft shops and markets useful for finding lots of small gifts. I try to keep the price low, but if you look for nice things to put in them you will end up spending £3-5 per cracker in my experience so making several can work out expensive. Plus you end up walking around shops putting things in toilet roll tubes...
There are more details and some gift suggestions on my blog