The adage is “work smarter, not harder.”
I don’t know if that holds true for comics (or anything besides manual labor, really). In order to get anywhere, being a viable creator, you have to put in a lot of hard work. A lot of times, that means working for free, which has a few things going for it: you get to see what it takes to make a comic book (and to see if you have what it takes), it lays the foundation for a body of work, and it shows the world that you’re a creator who finishes something. (This really means a lot in a world where things are started and not often finished.)
Doing free work will hone your skills until you reach a place where you’re able to charge for your services. Then, you should charge what you’re worth—and as long as you’re diligent in getting better, your worth should always be going up until you hit a place where the market will no longer bear your price.
Once you start charging for your work, don’t look back, and don’t backslide into doing free work again. Lower your rate, sure, but don’t work for free. It’s a level to reach, and there’s no need to ever go backwards.
There isn’t any other way to be a viable creator besides putting in a lot of hard work. I don’t care what your job in comics is—without the hard work, you’re not going to get anywhere. It may look easy from the outside, it may even be that you don’t feel like it’s much of a struggle to get where you want to be, but doing (and completing) the work is the important part. (And to be clear: “completing” means the book being available for sale.)
Once you put in the hard work, only you can tell what “working smarter” entails. Everyone’s workflow will be different, and what works for you may not work for someone else.
Maybe it’s time for a new adage. Work hard, then smart?