At this stage we look for the opportunity to decorate the harmony by the introduction of chromatic chords that fill in between chords in the static and dynamic harmony elements. This is optional and the number of chromatic chords used will depend on the style desired.

The repetition of chord I on beats 1 and 2 of the first bar makes this a good place for a chromatic passing chord. We do this by filling in the gap between the E of chord I and the F-sharp of the chord II with an E-sharp. This creates an augmented 5th chromatic passing chord. See book Chapter 3 for similar examples.

The last beat of bar 2 is a little devoid of interest and the G-sharp is not appropriately harmonised yet. We could add a chromatic passing chord. The (implied) E to F-sharp movement provides the opportunity for a chromatic filling-in step. I've insert an E natural in bar 2 at beat 3 to avoid the leap of an augmented 4th in the bass. The E-sharp sounding against the G-sharp of the melody can be harmonised as a diminished 7th chord. This supports good voice leading in all parts and therefore fits well into the background functional harmony.

The last beat of bar 6 is a good place to introduce a chromatic passing chord within the dominant prolongation. The dominant leading diminished chord (without a seventh) leads well into the chord I 6 4 as it often does (usually with the added diminished 7th.) The voice leading contains one chromatic passing note and one chromatic auxiliary note and supports the melody well.

See book Chapter 3 for more information on passing chords.