OK, Let’s start here:
Use Roman numbers for the step of the scales so that when we refer to Roman # I we will be referring to the first step of a scale. Use the same method for all scales.

EX. Key of C Major
C=I D=II E=III F=IV G=V A=VI B=VII
Key of F major
F=I G=II A=III B=IV C=V D=VI E=VII

I can now state that the most used progression is
V to I G to C in the key of C. C to F in the key of F.

Look through your lead sheets for V to I progressions. The V7 chord is normally used instead of a V chord. In the key of C Major it would be G7 to C instead of G to C. The seventh gives a strong feeling of movement.

Like I said in my post, just one thought, and then slowly build on it. This will give people a chance to absorb and research.

John C.