A word about Piano studies and music theory.
1-Go to the piano or keyboard and play a two-octave scale with your right hand in the keys of C, F, G, Bb and Eb three times each day – Maybe 10 to 15 minutes. Do this for 5 weeks and there will be a difference.
2-Don’t learn all there is about music theory, just add these simple substitutions.
Whenever you see a G7 going to a C Major add/Sub
G7 --- Sub Dm7 G7 C ----- V7 --- Sub IIm7 V7 to I
G7 --- Sub Db7 to C ------ IIb7 to C
G7 ---Sub G7 Db7 to C ------- V7 IIb7 to C
This does not fit with all kinds of music. How and when you use them is just another expression you may add to a song. Learn these Subs in different keys.
I can’t help myself, I love to teach, John C.