Here are a few tips to keep in mind if you are trying to come up with some really beautiful piano parts.

1. The Notes You Play

Try to intentionally create tension and resolve. You can play along to the melody of the song, or choose notes that harmonize with the melody. 

2. Song Context

Are you playing a slow song, a fast song? Is the song building, or dropping down? Try to match and compliment the song's energy and pace with the notes and chords you choose.

3. Room Environment

Are there lots of other instruments, or only piano and guitar? Are you in a large venue with lots of reverb, or a small space with only a few people? Some parts you play might sound completely different depending on the location and room you are in, so always keep that in mind as you practice and learn new songs. And as a general rule of thumb, the more instruments and parts that your team has, the less you might actually need to play. Listen to what the other members of your band are doing, so you don't end up clashing or fighting against their parts.  

4. The Sounds

Spoiler: you don't always have to just use a grand piano. Try an upright piano, or an electric piano. Use pads to add texture and fill space, instead of playing more. Sometimes playing the exact same parts, but with different Sounds are all you need to transform a song and take things into a new, fresh place. 

This intentional style of playing, active listening, and restraint will go a long way in helping you create beautiful, and inspiring music as a worship piano player.