Begin with a basic three chord progression in the key of C. The key of C is any easy beginning key for piano players and ideal for learning the basic principle of reading and playing gospel. The note in C are C-D-E-F-G-A-B. The basic three chord progression often used in gospel is a one-four-five. This means playing chords built on the first, fourth and fifth notes of a given scale. In C, those chords are C-F-G. In written gospel music, it's typical to see lyrics with the chord names written over the words, such as in hymnals. Gospel piano players often play chords and improvise the rest of the music.
Familiarize yourself with the one-four-five progression in C until you can play the basic triads (three-note chords) smoothly. You'll notice these chords are not quite big enough for a gospel sound, but they can easily be modified after you've learned the basic forms.
Add the seventh note of the scale to a chord to make it a seventh chord and the ninth note to make a ninth chord. These are two of the most popular extended chords used in gospel piano. They can be written as Cmaj7, C7 Cm7 or C9. Find the seventh note of C major by counting from C. The note is B. Add this note to the basic triad for a C7. Since there are only seven notes in a scale, find the ninth note by counting the first seven notes, then counting the C and the D again. The second note of the scale is also the ninth. The note is D. Add it to the seventh chord structure to make a ninth.
Play the one-four-five progression again, this time with the extended notes. Instead of C, F and G, play C, C7, C9, F, F7. To play a seventh chord, form the C major triad and add the seventh note of the C scale to this chord. The note is B. Add it with your left hand, in the bass of your piano, then simply leave the note out as you move to the final chord to resolve the progression with a C major triad played on both the bass and treble clef. Listen to the difference these added notes make. This is part of the gospel sound experience.
Play chords with variations in dynamics. The first chord of the progression may be played lightly, with the second a little harder. Play the third beat of every measure hard, really emphasizing the chord. This dramatic variation in light and hard is the second characteristic of gospel piano playing.
Pay attention to what you don't play. Lyrics -- the spiritual message -- is important to gospel music. Gospel piano players spend a great deal of time accompanying the choir, so overplaying doesn't work well with gospel music. Focus on the chords and simply supporting the melody of the singers. Leave room for the spiritual message of gospel.