Obtain the music for the song you are going to play. Most Christian contemporary songs have the lyrics and chords available online at websites such as christianguitar.org.
Memorize the proper scales and arpeggios for the song’s key.
Familiarize you hands with the prominent chords in the song. Typically the most prominent chords are I, IV, V, and VII. Memorize the various inversions of the chord and begin experimenting with adding augments and suspensions.
Practice the song. If you are playing the song with a worship team, it is always best to practice with them. This allows you the chance to determine who will play lead and who will accompany on the various parts of the song.