i would say its simply; time feel, articulation, phrasing and confidence. All things that can be practised.
Time feel: Practice different rhythms to a metronome or clave.
Articulation: Whatever your playing, try playing the notes soft and hard
Phrasing: Listen to lots of music and attempt to replicate it, transcribing is often used for this.
Confidence: Ask people to tell you how good you are