Finding good consequences -- consequences that work when there aren't natural ones to do the trick -- is a parental art form. For me, life is a lot easier when I have a plan for how I'm going to handle likely-to-occur problems. This is because I am not very good at making up effective consequences on the spot. When I'm het up I tend to lay on the consequences too heavily.
At our homeschool, the basic requirements of any school apply: you have to do the work assigned to you. I operate on the premise that if you don't do an assignment well, or at all, you need more practice. Because that way you'll get better at it, right? Right. So that's my Plan: you don't have to cooperate, but if you don't, you get more work.
Now, I know that everyone thinks they have strong-willed children. I've been known to think that myself at times. And I do, in fact, have one child who could out-stubborn a mule. This morning a different child managed to spend most of a half-hour complaining about a phonics sheet, without ever putting a word down on paper. Eventually I set the timer for five minutes, with the stipulation that if it went off and one side of one page was not done, another (double-sided) page would be added. And I reminded the child that life in its fullness was not an option until schoolwork was done.
Five minutes passed. The timer rang. I added another page.
Five more minutes passed. The timer rang. I added a second page.
Five more minutes passed, then timer, and a third page was added.
Five more minutes passed, then timer, and a fourth page was added.
Five more minutes passed, then timer, and a fifth page was added.
I was beginning to think we'd finish the entire year's phonics curriculum today when the child finally proposed doing a different page from the one that "I can't do", in order to stop the accumulation. I personally didn't care which six pages the child did, and graciously accepted the offer.
By then I'd reached the conclusion that the consequences I'd imposed weren't working. Another 30 seconds and I would have said, "You've earned five extra pages, but I can see that adding another one isn't going to help you get the job done. So I need to take a break for a few minutes to figure out another strategy."
When a child digs his or her way into a deep hole, it can be tough figuring out where the boundary is between holding the line and throwing in a rope to haul'em out. Sometimes you get it right, and sometimes you don't.
But if advantage #1 of Having a Plan is that you don't have to invent stuff on the fly, advantage #2 is that it's a lot easier to keep your cool for a solid hour. And advantage #3 is that when things don't go as you hoped, at least you have a Plan to reassess instead of a jumble of half-thought-out strategies.
An afterthought: I think any effective plan must center on making whatever the problem is the child's problem. If Mom is mad, or frustrated, or cranky, that's Mom's problem. My kids aren't interested in solving my problems. But they can sometimes be persuaded to solve their own.
Most kids do eventually get with the program. There are those who don't -- I have at least one who is very inflexible and prone to dramatic emotional liquidation at the slightest thing that's not right -- and if you have one of those I highly recommend Ross Greene's book, The Explosive Child.