A good way to make rice milk is to use fresh rice that is still hot.
Put all in blender, puree for about 5 minutes (until smooth) let sit for 30 minutes or longer, then without shaking pour into container being careful not to let the sediments at the bottom pour into the new container. Alternatively, if you are in a hurry strain through cheesecloth.
To complicate things and get a smoother milk, re-cook the rice with part of the water until it's very soft. Add salt and sweetners, soaked, blanched almonds or nuts and flavorings. Then run it through a blender, food processor, or juicer.