Ragging is a faux finish technique that is very easy to do, even on your first try. You'll end up with fabric-like finish that can be subtle or dramatic, as you choose. An average-sized bedroom can be completed in a weekend.
First, prepare the walls by washing and repairing any holes or cracks. Use painter's tape and dropcloths to cover up whatever you don't want paint on.
Apply a base coat of latex paint and let it dry. A light base coat with a darker top coat will give you a more dramatic look, so let that be your guide.
You can use many different types of material for this technique - old T-shirts, cheesecloth, burlap, plastic bags, chamois, terry cloth, even cloth diapers. They should be approximately 2 x 2 (feet) and you should have a dozen or more rags for an average room (about 12' x 14'). Different materials will create very different effects, so be sure to use the same material throughout the project. It's a good idea to practice with different materials on cardboard pieces so you can decide which you prefer.
Now for the fun part. Crumple up a rag (loosely) and dip it into your top coat of glaze or semi-gloss paint. Dab the painted rag on the wall (lightly). Dab, dab, dab, dab until the look becomes too light, then dip and dab some more. Re-crumple as needed. Switch to a clean rag when the one you are working with gets saturated with paint.
If you want more color and coverage, go over an area a couple of times. If you want something more subtle, wet the rag with water and wring it out before crumpling it the first time.
You can also paint the top coat of glaze or paint on the wall over the base coat and then rag it off. Same dab, dab, dab and recrumple method, but you're taking paint off the wall instead of putting it on. Again, you can wet the material and wring it out first if you want a subtle effect.
When you start faux painting a wall, you need to finish it in the same work session.
This technique works well with more than one color top coat, too. You could use a medium shade on the wall with a lighter version as the first top coat. Once that has dried, go back over the wall lightly with a second top coat a few shades darker than the base coat.
I also saw a wall done with a multi-color effect. The base coat was white, the first top coat was yellow, the second was red, and the third was blue - yellow was the heaviest application, red a bit less, and blue a bit less than red. Imagine the same treatment using pale green, pink, aqua and lavender, or any other colors that fit your scheme. Unique, beautiful, inexpensive, and easy! What more can you ask of walls?
Here's a Ragging video for a bit more how-to advice.
Choosing a wall treatment is a big decision, so here's more information to consider: