Find the pattern of the song. Gospel music is known for its patterns, especially Black gospel music. In Black gospel you have shouting rhythms, slow worship rhythms, up-tempo rhythms, and choir rhythms.
Lean on the bass line. Black gospel music in particular usually has strong bass lines. The bass line can help you find the chords that add to the song.
Play to the strength of the lead singer. What makes most gospel different from Contemporary Christian is that in Contemporary Christian you tend to play in tandem with the singers. In gospel music solos you have the singer sing a bit, then the music plays after the singer. This creates a call-and-response between singer and musician.
Learn every song you can in another key. Depending on the atmosphere of the church service or environment you're playing in, raising the key heightens the emotion in the environment. Gospel music usually modulates in half steps whereas Contemporary Christian modules in whole steps. Gospel music also modulates more than pop music will, so any knowledge you have of music theory will come in handy with this style of music.
Improvise with the song. On keyboard you can improvise by running up and down the keys within the scale that the song is in. Jump from major to minor chords to change the feel of the song or to go from chorus to vamp. Play chords in staccato (short, quick notes) instead of at tempo for an attack sound.
Play with emotion and expression. When you play with emotion the audience responds emotionally. When you play shouting chords for example, the audience begins to shout. When you play with expression, other musicians respond in kind. That's when real gospel music is created.