Language and Writing so difficult T T?

Whenever I write a compostion (be it English or Bahasa Malaysia), I can never manage to write one like the nice ones in the model essay books. When i do homework (composition homework), I spend hours thinking and writing then I look at the answers and think " Why can't I write something like that". i feel like i want to redo the composition. This also becomes difficult with compositions regarding events and social problems. For example: smoking, traffic jams and tsunamis. I mean, how am i supposed to brainstorm facts for that, especially in an exam? X+