Here's another idea from
Teaching Children Self-Discipline by Thomas Gordon that has helped me immensely, especially in those moments when Dorian is throwing his lunch across the kitchen, or dumping his milk all over his tray and the floor. It's the idea of problem ownership, which is something that I have vaguely understood in the past, but never yet applied to my relationship with my son. It's like this (p. 107):
[When an adult perceives that a child is misbehaving,] the "badness" of the behavior actually resides in the adult's mind, not the child's; the child in fact is doing what he or she chooses or needs to do to satisfy some need...put another way, the adult experiences the badness, not the child.
...When adults begin to see children as persons like themselves, engaging in various behaviors to satisfy normal human needs, they are much less inclined to evaluate the behaviors as good or bad.
...[This] doesn't mean, however, that adults will always feel accepting of what [the child does, but they can understand that] the child is not a misbehaving or bad child, not trying to do something to the adult, but rather is only trying to do something for himself.
I paraphrased a bit, so you could get the point of it without reading the whole chapter.
The author goes on to discuss strategies for working with young children, even babies and toddlers, such as finding out what they need, making some kind of a trade, and/or modifying the environment. These are great, and I already knew them, but for me, just stepping back and understanding that I am the one with the problem, not Dorian, helps me to see things in a new light and switch gears. And occasionally he is the one with the problem, and I can let him work that out too. Like when he has a poopy diaper but won't lie down for me to change it...
And on and on. Read the book. It's good stuff.