Not sure how old your child(ren) are, but the techniques in Transforming a Difficult Child with a points system- transformed my Ds5 in 24 hrs. I think because he believes he's in control. I mean he is anyways, because it is he who has to make the choice of what to do. My ds is so motivated to get the points that he can use as he likes. It's great!
Btw, I never thought my son was difficult, but is strong willed, smart, and other techniques were not working.
Good luck.