What's going on is this: if you were to look at what's being played under a microscope, you'd see a plethora of little pushes, pulls, ghost notes, mutes, variations in dynamics. All these transform the straight sequence of notes you're currently playing into the living, breathing soulful part you're aiming for.
And it'll come - you just have to do it without thinking about it. And that's where experience comes in.
It's good that you're thinking about at such an (presumably) early stage. But don't get too hung up on it. Chances are most of this will take care of itself subconsciously.