1.8Melody fit

Phrase 1:

Melody:

G G A G C B

Over C:

G = 5

A = 6

G = 5

Then over G7:

C = 4/sus

B = 3.

Beautiful.

The melody itself creates:

G7sus4 → G7

because:

C → B

over G harmony.

That is important.

You don't need to force extra notes.