The best technique that I learned this year was a new method to join a long-tail cast-on invisibly (to work in the round). It is a little awkward the first couple of times, but I’ve memorised it now, and I’m really not good at memorising things, so I promise it’s not too hard.
It’s the same principle whether you are using DPNs, magic loop, or plain circular, but the video handily shows all three. (You may also need a spare needle to assist in slipping stitches.)
If you want to read a bit of background from Assia Brill, the knitter, the full blog entry is here:
But the video shows everything quite clearly on its own.
What was your favourite or most useful discovery of the year?