This document provides tips and techniques for applying acrylic paint as an underpainting or base layer on a canvas. Some key points covered include: - Using pure turpentine to thin pigment for underpainting layers to allow it to blend seamlessly with subsequent layers. - Applying a light tonal ground first if an area will remain exposed to avoid a stark white canvas. - Avoiding too much medium in initial layers to prevent cracking and peeling as the painting ages. - Suggestions for cool transparent purple hues to use for overpainted warm layers in shadows, as well as color mixing tips. - Different approaches for underpainting like blocking local colors, contrasting colors