What are the most important defencive techniques for a southpaw?

Blocks, catches, weaves etc what are the ones I should spend alot of time perfecting?

Certain ones are more useful for a southpaw and some are southpaw only techniques.

Never have a lazy right hand jab or lunge with it. Make it snap back like a whip cause you are right there for their left hook, use your right elbow for defense too dont leave a space there for an angled sort of uppercut to get through underneath after you jab.

Learn how to move around the orthodox jab feet wise so you sqaure up only at the exact right time to follow his jab back with your right and re angle at the right times so you can set up to fire your left down the barrel first with less risk off their straight right hand, have your head off centerline when throwing it deep though your body movement like hiding it under his jab.

http://www.youtube.com/watch?v=rw1t2yAK_wU