Preventing your child from having a tantrum

If your child looks like he's just about to have a tantrum, the best way to put an end to it is to divert his attention.
Be chirpy, and think of things he likes. For example, if he likes animals, tell him "oh come and have a look at this snail on the window, it's carrying it's home on it's back!". Is he greedy? Say "Where has the cake gone? A little mouse must have taken it off, come and help me find it!" If you live in the countryside, "Lets have a race, I bet I'll win!"
If you seem chirpy, it will make him curious. Don't suddenly become moody if he starts having another tantrum, as he'll realize that it was all worked out.