As @nuggethead pointed out you have somewhat parallel motion between the first notes in the bass and soprano.
A slight improvement would be to change the soprano to A in the second measure.
- It gives a full triad.
- It changes the perceived parallel motion to contrary motion.
In an exercise this short, you really want to avoid repeated harmonies.
Measure 1 is primarily C major and so is measure 3.
Consider changing the soprano, which is repeating the note from measure one to another note, and another harmony.
G major, A minor, F major or even Bb major (assuming mixolydian mode) would all break up the monotony.