Learning the ropes with 22mo DD1, but DH and I have started doing something with seems to have massively curbed her burgeoning tantrum throwing and I wanted to share it in case it was useful.
Anytime we need her to do something that might cause a strop, we explain carefully what's going to happen and then say, "I'm going to count to three/five/ten and then: It's time to get off the swing / I'm going to put you in the buggy / I'm going to take mummy's earrings off you (etc)
Giving her a moment just to get used to the idea of what's about to happen seems to really help diffuse stress and 9/10 times she will do what I need her to do without complaint whereas before she would have had a meltdown. I can actually feel it calm her down as I count.
The added bonus is that increasingly I can also get her to do something herself using the same technique (come to mummy, put your book away, pick your bowl up and put it on the table).
It's essential to follow through, otherwise it becomes meaningless and it's important to explain what will happen when I've finished counting (rather than just counting) or she gets confused. It seems to be really working for us, I wanted to share in case it could be of use to someone else.