Apply an even, thin layer plaster to the wall with a putty knife, without drastic bulges or clumps. Smooth the layer with a trowel, and let dry completely.
Apply a second plaster layer, but instead of spreading it evenly, use the putty knife to create texture with short criss-crossing motions. Let dry completely. "You can use different colors for each coat; each additional layer will enhance the look," writes Anne Bold-Pryor in "The Naked Wall."
Apply a third layer of plaster. This layer will be smooth and even like the first layer, to create depth without sacrificing the texture of the second layer. Apply this third layer with a large trowel and smooth.
Sand the walls, as a final touch to bring out the noticeable shine of Venetian plaster. Take the hand sander and the sandpaper and sand the walls, being careful not to sand too heavily. Polish the uppermost layer of plaster to reveal the shine.