To me, great writers need to be efficient and committed. They force themselves to be productive under time constraints despite the distractions of daily life.
Great writers do good research. Writers often include fictitious details in the tales they create, but they do enough research to make their work believable. They gather enough knowledge to sketch an authentic picture in readers’ minds.
Great writers possess amazing imaginations, They can do exercises to bolster their imaginative prowess, but having the preexisting talent to imagine & invent is a huge benefit.
Finally, great writers have confidence. Putting your creative vision out there for others to criticize can be scary. But writers must be brave and willing to take risks in order for their work be distinctive enough to make a mark.