Better quality with experienced people
The key to a higher quality finish of any decorating work done is the use of better materials. When you look at businesses and are considering who to hire, look too for more experience. They know that it is better to use good materials rather than trying to save a few cents on cheaper supplies and equipment. Tile installers with experience will offer a better quality of tile or advice on what to use. You also get better preparation for the work, making sure damage does not happen to other surfaces.
Make the proper preparations
The proper preparation whether for painting or some other service like door refinishing is important. You should not skip certain steps because they add more time or are an inconvenience. You or the painters need to move furniture out of the room, or if that is not possible move it to the middle of the room and cover it. This is to protect it. Next, the curtains and rails need to come down. Also, remove the light fittings and then cover the floor with dust sheets so they do not get speckled with paint.
Before painting walls or ceilings, any cracks or damage needs to be repaired. A professional should rake out the loose plaster in them and then use a filler and when it is dry give it a good rub with some sandpaper. With woodwork like the doors or skirting boards, the damage needs filling there too, then sanded. Apply masking tape to areas you do not want to get covered in the paint like the edge of the skirting, switches, sockets and such.
The best method for painting if you are doing it yourself
Really it makes more sense to hire professional painters. They know the process better than anyone, have the equipment, the stamina and the skill. But if you do decide to paint you should work in this order. Start with the ceiling using a 2-inch brush cutting in where the ceiling and walls meet. When that is dry do the first ceiling coat using a roller. When dry repeat the same process. Two coats gives you a better finish. You can then carry out a much similar process for the walls.
Clearing up properly
Another reason to have others take care of all things decorating is that it means you do not need to clean up yourself. Any top professional tile installers, painters or such will put everything back as it should, first making sure they properly clean up after themselves!