Tyler Cowen makes up long lists of the blind spots of left-leaning economists and right-leaning economists. If I were asked this question, I would boil my answers down to one suggestion for each.

What I think left-leaning economists should do more:

Look for structural reasons for policy failure, rather than attribute it always to misguided ideology. Consider the implications of imperfect knowledge on the part of government actors. Also, consider that the existence and growth of special interests is at least partly endogenous with respect to policy.

What I wish that right-leaning economists would do more:

Look for structural explanations for the growth of the state, rather than attribute it always to misguided ideology. Consider the implications of urban density. Consider that as the economy becomes more complex, the potential dispersion in wealth due to differences in ability, information, and luck becomes very large, while the ability to overcome such differences with sheer effort probably declines.