Texturing walls is usually done via three techniques. First, the very popular and smoothest texture is an orange peel, ( looking like it's namesake). This texture covers a minimum of drywall flaws; it is easier to repair or replace a section of damaged drywall and match the texture; and it allows for the flow of the wall. Second, is called knock down. This is where texture is blown onto the surface and then by using a large flexible trowel you lightly flatten out the drywall mud. This technique is used for added wall ambiance and to hide a less then quality drywall job. If you want some notice to your walls knockdown is a more modern answer. The third wall texturing effect is called skip trowel. In this technique the drywall mud is usually applied by hand using a trowel. This is a more expensive, labor intensive wall texturing process that adds lots of movement to your walls. It is ruff to the touch, hides a multitude of flaws, and really adds to the experience of the room. All these techniques can be done lighter to heavier in thickness allowing for more variety of looks.