The most important cornerstone of your playing technique is BREATH, after all, the chromatic harmonica is FIRST AND FOREMOST...a breath instrument.
For you to continue to improve month after month, your base skills must be solid like granite...or growing in that direction.
Perfect your technique on Breath, Vibrato, and Bends and develop your ear by playing with and listening to a lot of music, and you will get better and better, even surpassing your goals.