Be transparent with the data. Stop making adjustments that are questionable and coincidentally result in increased warming. Stop blacklisting scientists who disagree with the consensus. Stop getting hacked and releasing emails showing people discussing how to "hide the decline". Stop gaming peer review by having the papers reviewed by a group of people who all agree. Stop making hyperbolic predictions about the future which are completely falsifiable and indeed end up to be false. Stop insisting that the models are completely accurate even though they have been completely inaccurate thus far. Stop accusing people who have questions about mitigation strategies as "climate deniers".
That would be a good start.