For me, this was the year I finally quit applying heat to extra-virgin olive oil in almost any application. To be honest, I'd always secretly suspected it was absolutely pointless to do something such as sautéing onions in good, fruity oil. After extensive A/B testing with canola or corn oil, I'll never put the good stuff in a frying pan again.
I've also finally really internalized how important it us to preheat the oven for a minimum of 20 minutes, or preferably 45, when baking. I know -- bush-league, but I used to get impatient.
Anyone else have any cooking revelations this year?