When you say left handed do you mean you knit from the right needle onto the left, hold your yarn in the left hand and knit English, or what.
I'm left handed, but I knit "right handed".
I'd think the right side of your project would still be the same as a right handed knitter, but you might be starting your row from the left edge rather than the right edge. Since you're turning the work and knitting alternately on the RS then the WS, etc. I think it's more a matter of reversing any patterns and/or shaping to have the piece come out correctly. For something symetrical like a sweater back it really shouldn't make a difference.
(Just thinking about having to read charts backwards gives me a headache.)
I know there are some other leftys on the forum who might have better ideas on this than I do.
Happy Knitting :XX: :XX: