I have a few different ways I start a painting. Having a variety of ways to start or work on a painting keeps things more fresh. Often I start from a central part on the canvas, and after getting it right, I move on to the next part, then to the next, and so on. But, today I just started by blocking in the lights and darks, followed by modulating the lights and darks to get something I was finally satisfied with. I don't think either way is right or wrong, and I don't know if either way is quicker. But the variety is fun.