Having a steady, consistent, smooth and relaxed strum, is the key to making beautiful music with your guitar.
Before you learn any chords, or learn any songs, you should familiarize yourself with the mechanics of strumming, so you can later focus on other things without worrying about strumming as much.
Proper Strumming Mechanics
The key to a good clean strum is a loose wrist and a controlled motion. The key to solid rhythm is an active controlled elbow. All motion should, ideally, originate from the elbow, not the wrist, when strumming. To practice this, put down your guitar, and strum the air gently, up and down, as though you were playing a guitar. Concentrate on keeping your wrist extremely loose and fluid, and originating all motion from your elbow. When, you strum downward, use your elbow to initiate the motion, when you start back up again, use your elbow. Allow your hand naturally with the motion of the forearm, as though you didn't have any muscles in your wrist at all.
Once you think you've got the hang of that motion, the next step is to apply it to your guitar. Pick up the guitar, make sure it is in tune, and make sure you are holding the guitar properly. If you like, use a pick, making sure to hold the pick properly as discussed in the previous lesson. Now, without forming any chords or doing anything at all with your left hand, give your guitar a nice clean downward strum using the technique you just practiced in the air. Feel how the strings naturally give way, and allow your wrist to move naturally slow down and allow your hand to gently respond to the force of hitting the string. Add a little speed and power, using your elbow, and you'll notice that you will form a nice clean strum. The less 'deep' your strum penetrates the strings (toward the body of the guitar), the smoother, lighter, and cleaner it will sound. Do this a couple of times, experimenting with different speeds and power levels.
Finally, try strumming upward a couple times, and then alternating. Once you feel comfortable, tap your feet to a steady beat and try to strum rhythmically to that beat, first using all downward motions, then alternating strums, first upward then downward.
Pick up the guitar for at least 5 minutes a day practicing this technique, while you are watching tv, until it becomes almost second nature. Then you are ready to start learning chords.
