We start out our days with "what are we earning today?" [if it seems that he didn't sleep well or if he got up out of the wrong side of the bed;)]...not a toy or gift, but wii time or computer time (how much time is set in advance), or a chocolate shake later. We cannot do time outs or other kind of discipline here.., it's useless. We don't take things away; again, we earn things.
The main thing that seems to work is doing tons of praising throughout the day "you are doing a great job today" - not BEING good. "I am so proud of you for making that really good choice." "That made her feel really good when you made that choice." etc. Comments like these, with explanations of why these things were good (not just an empty, repeated comment) before any bad behavior starts, have helped so much! Then, the earning thing just fell into place every day. And most days it is isn't mentioned at all because he is doing so well, he is proud of himself; and everyone is happy. He is homeschooled as well; so we don't have a lot of outside issues interfering that he can't tell me about, or that I don't know about. I am not saying that hs-ing solves all issues in any way.:)
Also, sometimes my son just needs a break when he is tired. He no longer takes naps; so between 4pm and 5pm, he is exhausted and tends to get crabby; and I make him lay down and watch tv in the living room or lay in his bedroom with no entertainment (he always chooses the LR - but it is still his choice;). He gets two choices when any issues ensue...both that I am happy with. We are calm around him, as we have to be. We all prefer a calm environment anyway.:) Our stress is his stress. Your DS may have a bad day if his teacher is having a bad day...another gifted issue of sensitivity to his surroundings. In conjunction, if there is stress in the home, he may be picking up on it (don't take this as criticism - just experience:).
Hope some of this helps.
