Have you ever attempted some DIY and made a real mess of it? A professional dissertator will tell you that the secret is in the preparing. If you prepare well, the project will run smoothly. If you fail to prepare well, the job will just get harder and more stressful. Here is our expert advice on preparing a room for painting.

Time to complete job: Preparing a room for a new coat of paint or paper will take at least half a day, including filling and smoothing old plaster.

Approximate budget: The basic tools and materials should cost less than £20 for most rooms.

You will need:

Sugar soap

Bucket and sponge

Rubber gloves

Interior plaster filler

Decorator's sealant

Filling knife

Sanding block or electric sander

Dust sheets

Step ladder

Dust mask

Tip: Before to begin, always protect yourself by using a dust mask and your floor by laying down dust sheets.

Step 1: Smoothing the surface Scrape off any flaking paint with a flexible filling knife and smooth the surface with a sanding block. For more tips on stripping back paint, see Paint Stripping. If there is wallpaper on the walls this will need removing. For tips on doing this, see Stripping Wallpaper.

Step 2: Repairing damaged plaster Sometimes patches of old plaster become loose or cracked. Pick out the loose areas with your filling knife and repair the areas with plaster filler. Work methodically over the whole room to make sure you have treated all the damaged areas. When the filler is dry, use an electric sander or sanding block to smooth any rough areas of plaster and blend in the new repairs. Very powdery plasterwork or new bare plaster should be coated with a coat of plaster sealer. Depending on the size that requires repairing, you may need to patch it up. Patching up plaster is beyond the scope of this article but detail of how to do this can be found on the UKTV website. Tip: Cracks around the skirting boards and door frames will spoil your new finish. Ensure that you remove any debris such as flaking pain and anything else that does not belong and then seal the gaps by carefully applying the decorators sealant.

Step 3: Cleaning Wash off any black mould with a solution of household bleach and leave to dry. Heavy mould or tobacco stains should be covered with a sealer coat of Anti-Damp Paint. Tip: It's essential to treat the cause of mould and damp patches before redecorating.

Step 4: Make a judgement call as to whether the exposed walls need to be covered with lining paper. If the walls have large repair patches or lots of tiny hairline cracks, covering with plain lining paper will provide a smooth base for paint or wallpaper. Hand this paper in the same that that you would hand regular wallpaper and then allow this paper to dry thoroughly over night. For more tips, see Wallpapering. And last but by no means leas, ensure that the surface is dirt and grease free by wiping down with sugar soap or hot water and washing up liquid. Don't forget to wash the ceiling as well if it's going to be decorated.