I have read many of the posts here and really do empathise with other parents going through these problems ....
I recently read "The Explosive Child" and really recommend this even if your child isn't extreme and explosive. It also applies to teenagers. It puts forward a new way of relating when continuing arguments and explosions are being destructive to your relationship. Here's a precis if you're interested!
Basically it describes 3 ways of parent/child communicating.
PLAN A. Parents' Will e.g. I want you to brush your teeth, do your homework, etc
PLAN C. Dropping some Expectations completely (this may be hard for some of us, but necessary unless you want constant battle with a sensitive or inflexible teenager or a teenager with ADHD traits etc ).
PLAN B. Collaberative Problem Solving. Broadly, it involves a few stages
(a) THE EMPATHY STEP "Empathy" e.g. child doesn't want to do homework, why might that be, its too hard says the child, what parts are hard you reply, and so on, the final answers can be quite surprising in a conversation. Its general empathy with information gathering, gently drilling (not grilling!) about what the problem might really be. Often children don't always know exactly what the real problem is, or find great difficulty in expressing it - one of the reasons for explosions! The book explains this very well with examples.
(b) DEFINE THE PROBLEM STEP - concerns are clarified - for both child and parent. Now the child has a real chance to explain his or her concerns. And the parent too! Again book very good at giving examples.
(c) THE INVITATION STEP - parent gives a chance for child to solve this problem, and then gives his or her ideas and input too (so the burden is not totally on the child). The solution might not be permanent e.g. if its unrealistic, but it can always be looked at again in the future.
Which plan you use at any time kind of depends on your child and the issue at hand. It may sound time-consuming, but as the author points out, the time consumed in angry arguments, outbursts and sulking plus everything that follows including remorse and so on, can take much more time and energy. Like others on here I really recommend this book.
(Was much less keen on "Get Out of My Life But First Take Me and Alex into Town" which had some great points re. independence but seemed to me to recommend total capitulation and acceptance of seriously problemmatic and even dangerous behaviour.)
Sorry for essay 