Comping is short for accompaniment.
When you play behind a soloist, whether he or she is playing the melody or an improvised solo, you are comping. Your job is to support the soloist, outline the changes and add
In the jazz field, comping has generally taken on a more specific role. It is usually referred to as comping if you play a syncopated, rhythmic style with your chords. Using up beats as often as down beats, “comping” rhythms are very distinctive and characteristic of a jazz swing feel. Most comping uses down strokes.
You need to pay attention to your chord voicings as well. Good rhythm with weak chord voicings will still sound ineffective.
After you have worked out your voicings for a song, start varying the rhythm. Think syncopated and keep variety in your patterns. It’s important to avoid a steady consistent pattern as that is more typical of strumming in rock, blues or country music. Listen to any good jazz guitarist when he or she plays behind a horn, bass, piano or singer. Unless the “Freddy Green” style is being used, you will hear effective samples of comping.
Apply this to as many songs as you can!