Working with Congress. IOTL Carter basically told Congress what to do, they resented it, and killed anything Carter wanted done.
If Carter doesn't approach the whole business as an outsider against those corrupt evil Washington politicians he'll see a far more successful legislative agenda.
Given that the economic problems were largely out of his control (although he did do a lot of work that Reagan got credit for both inflation and deregulation) and the Iran crisis would still likely happen it's clear that Carter is doomed in 1980.
However passing economic stimulus, a good energy bill, and more credit for his work in fighting inflation, deregulation, and reforming the military could lead to people seeing him in a largely positive light—but the economy overwhelming all other issues anyway.