The computer can be a tremendous asset as well as a big spender of your time. It is important to remember that you can spend hours clicking away on the computer, even after all the best planning. I have heard designers tell me that their process is going to the computer first and designing by trial and error. This is a good way to waste valuable time. Going to your machine should be the last thing you do to design. It is important to cultivate fine motor skills as an artist. The capability to build things and construct things should be among your talents. The author Malcom Gladwell writes about the 10,000 hour rule in his book Outliers: The Story of Success. It is believed by Gladwell, that 10,000 hours is the amount of time it takes to become an expert at something.
Practice makes perfect.
In other words, practice will make perfect. I don’t mean that your sketches will look like a well-crafted, photo realistic drawing—though they could. You don’t even have to be very good at sketching; the point is that your brain and hand have a type of connection that makes it very easy for you to convey your thoughts. That is more important. Ideally you will want to be able to expertly execute your thoughts, and communicate your ideas easily.
By the time you get to the computer step in your process you should be totally prepared to begin the final steps of the project. Your time spent at the screen will be significantly less, than going there first.