Proactive time-out can work well with mine (8, with AS). If I can see the signs that he's getting stressed out and getting ready to blow, I quietly suggest he might like to have five minutes with a book or the computer just to help himself settle down. We've been doing some good anger management work lately and he can see now that this is sometimes the right thing to do, and is getting quite good at it. Sometimes he can even recognise for himself that he needs time alone to calm down, but it's been several months of hard slog to get this far.
Discipline after the fact can be difficult. Behaviour 'experts' will say that you should never withdraw a reward or remove favourite toys, yet that's exactly what my son will respond to best. However, I would stress that J is capable of understanding that you gain rewards for one type of behaviour but might lose them for another, and is able to differentiate - not all SN children would be able to do this. And we're having a very successful back-end of the week after I took away his entire Lego collection, including precious Bionicles (after several warnings, mind you), and he's now earning them back one by one for more positive behaviour.
Positive reinforcement is definitely the way to go if it works for the individual child, but some, mine included, do need to see the negative consequences of negative behaviour before they can behave appropriately. It's like a reward-based strategy in reverse, in that he's getting an earned prize each time he behaves well, but he had to lose the lot before he was able to comply.
General day to day stuff works best for us with reminder charts, lists, timetables etc. Social stories are going down well just now, particularly the positive ones about achievement - always good to refer to when things are going pear-shaped.
Just my tuppence-worth.