I found myself needing to texture two walls in a basement room and not wanting to get a sprayer to splatter drywall mud everywhere. What I came up with was a very fast, efficient way to achieve a similar effect without renting any equipment.
Assume that the walls are smooth to your satisfaction, i.e. you have taped and sanded the seams, filled in the screw holes, etc.
1 box of drywall mud
8 inch drywall knife
Step 1: Water Down the Mud
I watered it down until it was about as runny as clam chowder. Just keep adding about a large handful in a bucket, then stir in water.
Rather than use a heavy mixer bit and drill, I just used a wire whisk from the kitchen.
Step 2: Trowel It On
Now use the Five Fingered Trowel method to apply the soupy mud to the wall. Spread it back and forth. I found I could do about thirty square feet at a time without the first part drying out before I was done with the last. As soon as a section of wall was covered in mud, I used my trusty Target bag, all balled up, and jammed it into the wall. This part took me a few tries. Initially I was kind of dragging the bag around, but what you want is to push the bag into the mud, then pull it straight back out so that you create peaks in the mud.
When you're done, the section of wall you just did should look peaked like a cupcake.
After a few moments of drying time, the thicker mud, closer to the wall, will be dry, while the thinner high peaks will still be wet.
Step 3: Let It Dry, Then Knock It Down
This was another part that took some practice. I kept getting antsy and scraping it off too early. If that happens, you get a flat, smooth spot about the width of the knife. I also found that the best technique seems to be minimal pressure, and keeping the blade almost parallel with the wall. Keep moving the knife in different directions to eliminate any obvious knife edge gouges.
Step 4: And Here's the Finished Product
This ended up being something that I was able to complete in just a day ( two walls), with only one half of a box of joint compound and no additional equipment required. The texture is random and spread out enough to create some nice shading now that it's painting. For a rube, I think it came out OK.
I have more work coming up, so any feedback regarding other drywall techniques would be greatly appreciated.