depends on the question but:
intro - address the question, define what fiscal policy is and some of the objectives it targets
paragraph on general recent trends - talk about the GFC as fiscal policy was used majorly in response, more recent goals of fiscal consolidation
then I would do a paragraph each on how fiscal policy addresses certain economic issue/objective
economic growth, unemployment, inflation (more for monetary policy though), external stability, income distribution, environment (ditch this if you run out of time)
conclusion
In each paragraph incorporate theory and trends together. Don't have random slabs of theory and then chunks of trends only at the very end of the essay as it doesn't convey a logical/argumentative voice. sort of rough but hard to say coz no specific question