Before trying out these ideas in your room, prepare the wall. Wall preparation is a crucial step in the painting project because without it even the most alluring and brilliant color schemes lose their aesthetic value, fade easily, and won't last long. If you have a hollow wall, remove the old plaster and paint layers. Then, apply new plasters before painting. This way you will make sure that the painted colors will last long. If you have a wallpaper-covered wall, remove it before the project. To paint a room with opaque hues, scrape the paints. But avoid using force while scraping the wall since it damages the fine plaster. Alternatively, get a special paint removal product.