There is no proved way to get your own style.
However, I have an idea to build up our style. Can you draw your family or friends in your MANGA style?
We have "NIGAOE:MANGA style portrait" in Japan. Though it might be not Japan specific, there are many people who can draw NIGAOE in Japan.
There are many web sites to learn NIGAOE like this
One I tried to draw NIGAOE and failed because I have no basic style to draw person. I think you can draw NIGAOE based on your current style.