This movement is an interplay between rhythmic and melodic moments. The opening melody is more melodic. The bow arm's elbow should move more horizontally than vertically. No flapping of the elbow. The fingers should be more active in the bow hand, not just reactive.
Character is the most important thing in music.
Exaggerate, go overboard musically. Don't let rhythmic ornamentation interfere with melodic aspects. Let the impulse play itself out. Sound comes from the shoulder from a rhythmic swing. Practice with a slow bow close to the bridge in order to gain control over your tone.