Like many artists, I struggle with the expectation of a style. I try many from colour to line art, and I still find in my third year of illustration trying to do them all.
But, I personally think the way artists and illustrators should develop a style Is through practice. Drawing from photographs and life is important realisation for developing a style as an artist. But most importantly, drawing artists as inspiration. I am inspired from many artists , from John tenniel to Andy Warhol.