Here's some examples to modulate keys
From C to C#
C G / C chord
Bb Ab / C chord
Ab Eb / F# chord
C E Bb / Ab chord
C# Ab / C# chord
From C to D
C G / C chord
Bb Ab / C chord
A E / G chord
C# F B / A chord
D A / D chord
From C to E
C G / C chord
Bb Ab / C chord
B F# / A chord
Eb G C# / B chord
E A / E chord
HOPE THIS MAKES SENSE....THE TRICK IS
C G / C - that your I chord
Bb Ab / C - dom7th on the LH
Now the next chord....u can do either (from these 3 examples) just playin the 2 of the key u want to go to!!!
So let's use numbers..using Major scale
half key...
LH / RH
1 / 1 CHORD
dom7th / 1 CHORD
NOW WE GOING TO THE HALF KEY....SO USE THE MAJOR SCALE OF WHATEVER THE HALF KEY IS
2 / 4 CHORD
5 / 5 CHORD
1 / 1 CHORD
whole key...
LH / RH
1 / 1 CHORD
dom7th / 1 CHORD
NOW WE GOING TO THE WHOLE KEY....SO USE THE MAJOR SCALE OF WHATEVER THE WHOLE KEY IS
2 / 4 CHORD
5 / 5 CHORD
1 / 1 CHORD
Major 3rd key...
LH / RH
1 / 1 CHORD
dom7th / 1 CHORD
NOW WE GOING TO THE MAJOR 3RD KEY....SO USE THE MAJOR SCALE OF WHATEVER THE MAJOR 3RD KEY IS
2 / 4 CHORD
5 / 5 CHORD
1 / 1 CHORD
SEE THE PATTERN?? I HOPE THIS HELP YA IN SOME WAY....