How do I paint a blue sky with Acrylic Paint

I am an Acrylic Painting Instructor in Oregon. In many of my Acrylic Painting Classes, we begin the painting with a blue sky. Here is how I paint a blue sky. Start with Titanium white, load your damp 1" paint brush. Paint Titanium white onto your acrylic paper or canvas about 3/4 of the way down the paper. Dip your brush with white paint still on it into a little Phthalocyanine blue, just enough to cover the tip of your 1" or large fan brush. Starting in rows horizontally from the top. Blend this blue into your painting by painting criss-cross brush strokes starting at the top of your painting. Then pull your brush from one side of the painting over to the other even painting onto your tablecloth. Start blending the next row, blend with criss-cross strokes, with a single stroke of your brush from one side to the other. Do a couple more rows with the same light blue brush, without getting any more paint. As you blend each row your sky will be darker at the top of the painting then it is in the middle. Learn more about taking an Acrylic Painting class, http://www.dkboljat.com/painting-classes.html