I don't want to derail this topic with all of the things I did personally because my medium, genres and working style is different from what you do and thus what specifically worked for me will not directly work for you. There's no quick and simple way except for the few who get noticed fast out of sheer luck. If there was, I'd definitely tell you.
But yes, the road has been long. I've been posting my art online in various places for nearly 10 years and doing comics specifically for 4 of those years. My comic work times throughout those 4 years has been "any hour I can spare", alongside school at first and then a waiter job i had for a while after I graduated. Thus, the best advice I can give to any artist or writer is to be active, never give up, and above all do what you do because you love the art itself firsthand and you won't be disappointed regardless of how it turns out.
I should probably also mention that different people break through in different places and different ways. While obtaining free readership online has worked out for me, if I were to get in a crisis tomorrow that forced me to attempt commissions noone would be interested. I have tried it several times and the response has been a choir of crickets. Similarily, traditional publisher comic business has rejected me several times.
So basically look into the different ways you could turn your writing into a profession and give as many of them as possible a good try.
