Having good rhythm or keeping time is usually the most challenging aspect for beginning guitarists. When learning a song or exercise always learn to play it very, very slow first. Students usually try to play faster than they are capable and find themselves making the same mistakes over and over which leads to frustration. A good analogy is learning to drive a car. If we jump into the driver’s seat without ever having driven and put the pedal to the floor we would either have a wreck or give the driving instructor a heart attack. Always practice slowly in the beginning. As you get comfortable with the tune you can speed up the tempo.
A metronome is an essential tool for the practicing musician that will help develop a sense of rhythm. Also, many books come with C.D.’s that serve the same purpose as a metronome. Band in the Box is great software that gives you an automated band to accompany your playing. Any of these products will help your rhythm. The importance of playing with a metronome can’t be stressed enough.
Students tend to use all down strokes when learning without an instructor. The longer the student plays this way the harder it is for him to correct his technique. Using the proper technique with a pick is extremely important. It is usually appropriate to use down strokes when playing whole, half, and quarter notes. However, when playing eighth notes you should use alternating picking (down and up strokes). In common time the down strokes should be on the down beats which are the numbers (1, 2, 3, 4). The ‘up beat’ in between the numbers should be up strokes.
Henny Youngman once said, “The self taught man usually has a lousy teacher and an even worse student.” A good instructor will help you to avoid bad habits that are hard to break and offer insight that takes years to accumulate. A good instructor will teach you music theory as well as how to read music.