Originally Posted by Mike Brewer

I am a natural right hander, but I fight southpaw. Have since I was six. The "formula" for beating us left handers is pretty cut and dry. Circle to the outside of our lead hand. This kills the jab and makes the power shots harder to land. Use the straight right as a lead blow from time to time. If you're circling correctly, it will land with surprising ease. It slips through the guard the way your jab would on an orthodox fighter. Work the left hook to the body. A southpaw puts his liver up front, and your body blows will have more effect, so use them. Try this strategy, and let me know how it works out. I'd be willing to bet that you'll enjoy some immediate success. If that works out for you, I'll add to it.

Summary:

• Circle outside his lead hand.
  
• Throw the lead right hand (use your cross the way you normally do your jab) from time to time.
  
• Work the left hook to the body.