One of the important things for a church pianist to do when accompanying the congregation (or anyone for that matter) is to know when to play. When playing for a group it is important not to overshadow the singers.

When accompanying the congregation on piano during worship it is important to use the piano as a guide and a support.

Many times a pianist can play so loud and hard during the full song that the congregation is drowned out and it becomes more of a one act show.

In order to avoid this take time to play during the spaces and pauses in a chorus or hymn.

Some examples are to play a strong introduction to the song so the singers know when to come in and then taper back a bit not necessarily playing each note of the melody.

And also to play a fill in during parts where the singers take a breathe such as between lines of a verse (whenever you see a comma) that is a good spot where you can add a bit more to your piano playing to encourage and uplift the singers.

A very good way to practice this technique is to sing along when you are practicing alone. Practice with easy songs and note when you are taking breathes and some of the things you can do on the piano to fill those empty spaces.

Good fills for spaces are chord progressions to move to the next chord in song.  A run of some simple notes in the right hand or the left. More dramatic songs can even have a set of bass notes in an octave to emphasize the dramatic nature of the song.

The possibilities are endless but try not to over do it. You want to embellish not take over.

If you have trouble coming up with your own fills pick up a book such as Complete Improvisation, Fills & Chord Progressions Book