Remove the door from its hinges if the hinges will be in the way of the painting, or cover the hinges with painter's tape to prevent the hinges from becoming ruined by the painting process. Use a screw driver to do this. If you leave the door in the frame, close it securely during the painting process and cover the doorknob with a bag, taped on with painter's tape. If you remove the door from the frame, remove the doorknob.
Clean the door with a sponge and soapy water. Dry the door with a soft, clean rag.
Sand the door with medium or fine grain sandpaper, if the door has been painted previously, to remove any chips and smooth any pocks in the paint.
Choose the type of faux surface you wish to paint on the door, if you have not done so already. Study the surface you wish to paint and determine what materials you will need to achieve the desired textures you see in that surface. If you have not previously painted the particular type of faux surface you've selected, practice on a scrap board before applying the faux surface to the actual door.
Paint the base coat using a roller and give it time to dry. As it dries, prepare the painting materials for the subsequent layers.
Paint the subsequent layers on one side of the door and let the door dry.
Paint the subsequent layers on the other side of the door and let the door dry.
Reattach the door knob and reattach the door to the frame, or remove the painter's tape from the hinges and door knob, if you left the door in the frame.