distance: stepping into punching range only when ready to attack then stepping out and maintaining a distance that would require an opponent to step in under fire. ex. pacquiao did this very well against hatton, who jumped in with a wild right hand that pac ducked under and countered to hurt hatton the first time. also, judah/ cotto, the first counter uppercut that had cotto dancing.
movement: generally, when circling your opponent, a southpaw is taught to step towards the opponent's jab hand so, for the opponent to properly hit you with the straight right, they have to reach. this exposes them to a variety of counter choices. this also helps keep the southpaw's right foot outside his opponent's left foot. ex. pacquiao/ de la hoya. when roach/ lederman kept saying pacquiao is "turning" de la hoya.
proper head movement: such as changing levels, moving the head after every punch/ feint. ex. lucian bute's vicious left hook to the body seems to be set up by this and proper distance. as his opponent rushes in, he takes a step back and slides under the right hand. this exposes the whole of the right side of the body and gives him a safe angle to step out from.
attack: the same weapon that works for the orthodox fighter, works for the southpaw. the difference is that the southpaw is probably used to seeing the angle of that straight right, it's not always the same the other way around. ex. i believe it was mosley's trainer in the 2nd winky wright fight that said "don't wait on a southpaw". roy jones went on to explain that most orthodox fighters aren't accustom to the angles the punches are coming from enough to fight in a reactionary fashion. ex. pacquiao/ cotto, where cotto was getting tagged with punches he did not see coming based off hand speed and angle while on trying to block whatever attack pacquiao was throwing.