Sometimes the simplest tasks can go a long way in giving your newly painted wall a fresh sheen to it, and while they may seem obvious if forgotten they can really cause an issue! That is why I always recommend that you do a quick dusting of your walls before starting in on the heavier cleaning. Routinely dusting the walls, even when the wall has been relatively recently painted, is one of the keys to maintaining a tidy coat of paint. According to a handy guide from Sherwin-Williams you should avoid cleaning a newly painted wall with warm water for at least two weeks. Any earlier and, obviously, you run the risk of smearing and ruining all of your hard work. It goes without saying that washing away all that hard work would be totally disappointing.
After the paint has aged a bit, you are going to want to vacuum the walls to remove any obstructions or knicks in the paint. Drywall dust also poses a unique problem when it comes to the issue of cleaning newly painted walls. While it can be tempting to take a wet rag to the wall to quickly remove the dust, remember that you need to let that paint set before you start putting water on it. As frustrating as it can be to stare at the drywall dust on the walls, outside of dusting there is not a whole lot you can do about it. Wait patiently until the paint is completely dry, at least 72 hours, and then feel free to use room temp (or cold) water on a washcloth to quickly remove that pesky dust.
Successfully painting a wall is likely to instill a sense of pride in your hard work, and the last thing you want to do is ruin all of that hard work by not taking caution when cleaning during those crucial first few weeks. With the tips listed above, you are certain to keep that beautiful wall in tip-top shape for a long time!