My son was (and is still) incredibly stubborn and persistent. Distraction rarely worked for us because it just wasn't possible, he's so single-minded. For me, finding ways to safely engage in the desired activity, plus a lot of explaining about why/what is dangerous worked. At about a year, he became obsessed with knives. I'm pretty sure this isn't in any parenting book, but I figured that I'd be better off teaching him the right way to handle a knife because one way or another, he was going to get his hands on one the minute I let my guard down. So I taught him about the handle and the blade, and took the time to carefully supervise him with knives as much as possible until the interest passed. I did the same with other things he was interested in like hammer/nails, outlets, candles, and the microwave. This has helped him accept and respect the few absolute no's (like our gas stove) much better.
He also had a lot of tantrums/getting stuck in a loop at that age because he is such a perfectionist and couldn't do what he wanted. Modeling with stuffed animals helped (he got to be the one to tell his naughty "friends" no or console them for not being able to do something yet or we could teach them how to do something when he wouldn't let me help him).
Now that he's three, I can ask him what he's tried, if it's working, and what else could we try? If he's getting really stuck, I ask, "Is this important to you?" sometimes he says no and it diffuses the situation. If he says yes, then I tell him, "okay, we'll keep trying until we get it as long as you're calm." He does have to ask nicely or there are no results, and if he's spinning out of control then we put the item away.
One and two years old were very hard for us with the desire/skill mismatch, but three has been better.
