During our lace knitting retreat, we talked about different ways to make left-leaning decreases. The talented Evelyn Clark has created a sampler dish cloth so you can practice four types of left-leaning decreases. They all lean left but each is slightly different; practice all four to add to your knitting repertoire.
While you are at it, browse Evelyn's Web site and look for her designs published by Fiber Trends. Her lace patterns are always beautiful, with clear instructions.