I now have clean walls in the bedroom and bathroom.
Before I started I consulted with Google, and found a site with detailed wall cleaning advice. Apparently I was supposed to vacuum the walls, wipe them over with a dry dust cloth, put down plastic sheeting taped to the skirting board to protect the floor from drips, spot clean any marks with a concentrated cleaner, wash the full walls with a wet cloth and mild cleaner, wipe down the walls with plain water to rinse off any residue, then dry the walls with a towel. Well worth the small amount of effort, and I only need to do that every couple of months. Apparently.
All I do is dust the wall,. Get a bucket of warm soapy water and a textured cloth. Wring it out and start at the bottom of the wall, working up. Dry as I go with an old flannel.