Some do’s and don’ts of painting:
Don’t – paint directly out of the paint can. If you’re up a ladder and it gets knocked off, you’ll have 10 litres of emulsion to clear up. Meanwhile, it can transfer debris from the brush back into the pot, leaving lumps in your paintwork. Decant some into a smaller container bucket instead.
Do – paint the edges of the wall first, slowly fanning the brush out sideways to ensure a straight line (this is called “cutting in”). You can then fill in the rest using either a paint brush for a small wall or a roller for a larger area.
Don’t – load the paint brush with too much paint. This is a classic mistake of DIY decorating that leaves a lumpy finish. The paint shouldn’t come more than halfway down your brush.
Do – paint using the tip of the brush so you don’t leave brush marks. Emulsion paint should be laid on in different directions (not just vertically as most people do it), so the brush marks blend in and don’t catch the light.
Do – allow the correct amount of time (four hours for emulsion and 16 hours for oil) between coats or the solvent in the second coat will smear the first.
Do – kill off any strong colour on walls with a layer of white emulsion before adding another colour. - The Independent