The best paint for stair risers is semi gloss which has already the primer. For the rails and treads, you need to use the floor or porch paint. While putting the first coat, you need to tint the primer using the color you have chosen. You can opt for the low luster so that it can look less dust and it is not that slippery. You can start by using light sanding and you can easily wipe down the sand by the use of a damp microfiber rage. Before you start to paint, you should tape. You need to let sometime pass before you can paint two different colors if you are using a white and dark color.