I think that art style is one of those things that artists are always worried about because in a sense, the art that a person creates is their identity, and not knowing one's art style is kind of akin of not knowing who you are, and that's absolutely frightening.
I was recently in the dumps in trying to figure out why I'm not happy with the stuff that I'm creating. It feels like I'm forcing myself to be someone that I'm not. And truthfully, that is completely the case: trying to force a style isn't going to work. Another thing for me to note is that everything that looks cool doesn't need to make me insecure about my own style.
I like all sorts of genres of art, and they all look great to me. I can appreciate abstract, realism, doodly stuff, and sometimes even contemporary art. But being open to all of these sorts of art can make for quite a struggle: I don't know where to go with my art, because everything is so interesting and seems so cool to delve into.
I realize that it's a matter of knowing my preferences and my natural disposition. I thought about what came naturally out of me instead of what I coaxed and forced out of myself, and when I looked back at all of my old pieces, there seems to be a pattern. I can't really put into words what type of pattern arised from all of my past pieces, but it's certainly there. And it became obvious to me that the pieces that I like to show to others in public are those pieces which weren't really "forced". I had conceived the idea and went through with it as naturally as breathing, instead of trying to force myself to emulate artist X, trying to render like artist Y, copying the subject matter of artist Z, and so on.
Really, my style is already ingrained when I create ideas for my pieces. I don't force it, but I just try to emulate what I see in my head as best as possible, and that becomes my natural style. No sort of forced stylistic constraints on my part. Of course, influences arise from other artists, but those influences are already in the ideas which are inside my mind, not really something that I try to force out of myself when I try executing the piece. I suppose style in this case is already a part of the idea conception phase and not a part of the execution. What you imagine your pieces to be already has your style embedded into it. That may change over the course of one's development, but it's natural and specific to each and every artist.
Also, my preference for the process changes how my ideas are conceived as well, thus shifting my style. I believe that ideas are inspired as a result of knowing what one is capable of. So if you're able to draw people very well, suddenly the ideas that the mind is churning out considers the limitless possibilities of integrating people into one's work. It can also be just a natural interest (ie. I would like to draw people so my ideas always have people in them) as opposed to being spawned as a result of one's competency, but this is merely something which I have observed with myself; I'm not entirely sure if it applies to others as well.
An example of preferences shaping my ideas and thus my style is my process for rendering. I hate doing line art. Don't get me wrong, I love artists who can do line art well and make it look good, but my goodness do I start losing my own mind when I start doing it myself. It legitimately drives me insane. Also flat rendering for colours (ex. ligne claire) also drives me mad. Again, I love all sorts of art incorporating that type of rendering, but doing it myself makes me itch all over. It feels wrong when I try to do it myself, oddly enough. It's merely a preference of how I do the process. Others may find that their preference for the process is different, and that's fine.
I do feel like my process is similar to that of a traditional painter, despite being primarily a digital artist. I typically start with a rough sketch, and then immediately jump into painting and colouring. No line art/inking process, nothing. I just jump straight into painting. I honestly love doing it that way and it makes art that much more enjoyable for myself, because I'm more into the painting and rendering process rather than the drawing process. This inevitably influences my style in some way, and that's just purely preference for the process. I didn't really need to force it or anything, nor did anyone tell me to do it that way. It's just part of my preference and thus became a part of my style.
I suppose this is all to say that style is something that need not be worried about so much, because the ideas and concepts that come naturally to one's self already have the essence of one's style ingrained into it. I may try to draw like other artists, but more often than not how the idea looks in my head takes precedence before any sort of stylistic studies that I've done of other artists. In time my ideas will start shifting as a result of my tastes developing, and thus my style will change over time.