Ideally, what Gaga should do is erase ARTPOP, but yeah...
Other than that, people already have a certain image of her. And short of going back to brown hair and singing jazz, she won't be able to change that perception.
The key as a global popstar is to always keep your options open. Gaga closed in on the narrative of a weird, misunderstood freak and let it define her image. She's permanently *over. Katy Kats won.
*she still has a fanbase, and she'll still "succeed" in music, but she'll never outsell major popstars again.