After the plaster, you need putty wall.
Putty is applied to the wall in two layers. After the first coat has dried, apply a second. For preparation of putty, you need to take a bucket of water, a spatula and pour plaster on the surface of the water, and thoroughly kneading.
All the mixture is ready for application. Ok, after the completion of all work, you need to clear the wall with sandpaper, from ledges, irregularities and so on.
That's all the work on the finishing wall putty.