hi Deniz,
Yes, I make a style by "studying" (listening many times) mp3. By doing that, I first try to isolate rhythm pattern (usually drum section & bass). That is, I try to imagine what and how I need to play in single rhythm pattern. In some songs that pattern (or even rhythm) can change in the middle of the song and that can make things quite complicated. Usually I can recognize quite soon if I have enough skill to continue or not.
After that I concentrate on rest of accompaniment: guitar inserts or strumming, background pad instruments and other inserts (i.e. harmonica, brass instruments, etc.). That is, I try to imagine how my MAIN A variation will look alike.
And once I have a "picture" in my head, I usually start creating a style either with drum or bass. But that also depends on music genre. For example, for "good old" Fats Domino songs, it can be easier to start with piano (because piano rhythm pattern is more dominant). Once I manage to create base rhythm pattern (i.e. drum and bass), it's usually easy to add the rest.
Of course, it does happen that I need to adapt some instruments, because it makes no sense trying to make exact duplicate of original. However I do try to make it sound "like" original. Actually I don't wish to make exact a copy -because I don't wish to make karaoke. It should sound how "my band" plays the original -I hope that makes sense.
Anyway, it's important that I'm happy with my MAIN A variation before I continue with the rest -because all other variations, intros, etc. are based on MAIN A.
I'm not style creator expert and I'm still in process of learning... but the feeling when I play with "my band", is priceless.
Bogdan