Rule of 1 A one piece band plays all the music. In a five piece band each member should play a 5th of the music. A temptation for keyboardists, particularly if you have come from a classical background is to overplay and step across other peoples parts.
Play just with right hand
If you struggle with overplaying one option is to literally tie your left hand behind your back and purely focus on what the right hand plays.
Same spectrum as lead guitarist so don’t clash.
Electric guitars and keyboards often play in the same octave so it’s easy to clash with each other. Try to listen to each others’ parts and use different or complementary octaves/sounds. Be careful if either of you are into adding extended or substituted chords as they can clash too. If you can’t hear each other then at least look at each others fingers to coordinate rhythms.
Don’t clash with bass player
Another thing to be careful of is adding pushes into the left hand bass notes. If the keys player pushes a note a 16th ahead to add some syncopation but the bassist plays right on the beat the listener just hears two indistinct bass notes right next to each other which just makes the overall groove sound confused and muddy.
Smooth voice leading
If you play block chords in the right hand the biggest jump forward you can make is to learn chord inversions I.e. the same chord notes but not necessarily in the same order so that one chord seems to flow more smoothly to the next with the least amount of interval jumps. This practice of smooth voice leading is often used by backing vocalists when harmonizing. They try to naturally find the nearest harmony note to the one they’ve just sung so as to not make awkward sounding big jumps.
Don’t rely on transpose button all the time
Even some very well known worship leaders and musicians are guilty of this. Don’t be afraid to touch the black notes! If you always stick to C then start by playing in keys with just the odd black note. So try G, then D, then Bb, Eb. – Go on, give it a try!