I have 7 of my 10 grand-children who are left handed, it is a challenge to teach them to knit. One of the easy ways that works for them is to knit on two circular needles. You only have to knit in the round.
I'm a lefty but I do most things right-handed (it's a right-handed world, after all). However, I have become very ambidextrous and I find that knitting stockinette is easier for me if I knit the purl row as a backwards knit. In other words, I never turn the project - I simply reverse directions and knit backwards. It goes SO fast for me!