Cut all of the tops off of a basil plant. These are the parts that shoot out of the middle of the plant, not the leaves. They often also develop some white flowers. I typically either remove the white flowers or don't use the shoots that have too many flowers on them).
Place them loosely in a brown paper lunch bag. You don't want them to be packed too tightly, so use multiple bags if needed.
Loosely fold over the top to close and keep any dust out.
Let sit for about a week (or if you are like me, until you remember and get a chance to do anything with them).
Check that they are all dried. Take each stem and slide all of the dried pieces of basil off the stalk with you fingers and into a bowl. Discard the stems.
Place them in a glass jar, label and place in your spice cabinet. Use as you would any store bough dried basil. Usually I crumble it up a bit more between my fingers as I'm adding it to my recipe so that it is in smaller pieces.