There are so many methods out there but for me I usually use larger chords to fill out my sound like 13's, 10's and 11's.
Some examples of these chords are:
C-E-G-A#/D-F#-A (C13 FLAT5 )
This is an example of an chord that I would use on the organ for a larger sound. What you can do with this chord is tranpose it the other keys, play it in all of it's inversions, and try to attempt to maneuver on the organ with these types of chords. If you have any more questions let me know.
God Bless