Two possible ways to fix a consistent left shooting.
1) Try rotating the bow more clockwise (if you're right-handed and holding the bow in your left hand that is...). I tell my students to start at approxamately 45 degrees and see where that places the arrow. The idea is that the two fletchings on your arrow form a "V" under your eye that acts as an almost imperceptable rear sight to your vision. You then draw an imaginary sight line along the length of the arrow directly to the bullseye. If you can't draw a straight line to the bullseye, then your arrow certainly isn't going to fly straight to the bullseye.
2) You could be plucking the string. If you keep the muscles in your fingers tight at the moment of release, you could be inducing vibration into the string which will inevitably throw your shot off. Instead, think of a release not as something you are "doing" but something that you "stop doing." A release is simply letting go of the string, and it takes some work to teach your muscles to fully relax upon release. To help, when you release, let your fingers come back and touch your ear.