What would you say is the most important thing an artist can do?

The most important thing an artist can do is be ready to step out of their comfort zone. You gain nothing by drawing the same picture and poses. Be ready to try something else, or even a different pose for pictures. Being a spoiled brat who is unwilling to try anything different is gonna cause problems. 

Also, don’t use pre-made assets. In some cases, it works, mostly as a baseline start up… But NEVER use pre-made assets in the final product. That’s just awful.