Write something using G Am Em D
Check out the video for more details and to watch me give some examples.
If you get into the habit of writing a little something once a week or so, you'll start seeing guitar differently. You'll figure out songs quicker. You'll learn new things quicker. You'll have more ideas when you jam with people. You'll be a better band mate. There are only benefits to learning to write, even if you have no intention of becoming a songwriter!