This is the ultimate test as to whether or not to play a run at a particular place in the music. Your ear must be critical of your own playing, and constantly asking questions such as:
You should always be thinking about your playing, so that you may better serve in your role as a church pianist. Listen to others when they play (especially good musicians) to see what you can incorporate into your own playing. Most importantly, remember that God must receive the glory in the music service. Play well, and give God all the praise and honor for what He has done through you.