I think i took a bit of a different approach with the essays from you all. Unlike english/history essays I was told that economics essays should be straightforward and mathematical.
Most questions, even if they are a single line can be divided up. I find it really helpful to do a quick skeleton to make sure i will cover all the areas/issues/solutions to be addressed. The beauty of eco is that you can really extend any question indefinitely in any direction you want if u go with the old cause/effect/hypothetical result vicious cycle.
Make sure that you think about *all* possibilities. If its on globalisation, bring in influences on monetary and fiscal policy, which can be extended to unemployment etc...
I learnt my info in lists (just my learning method, but i can recommend it), and i tended to devote a para to each point or 2. depending obviously on the nature of the question. For globalisation it may be : trade, investment, finance, technology, labour etc....
A conclusion may or may not be necessary, depending on verb used.
There is no *definitive* structure, and methods work differently for each individual. I will just reiterate the importance of practice essays. After several of these, u begin to devlop a system. Especially once u do a few on the same topic. e.g employment for me had the generic divisions: cyclical, structural, frictional/seasonal etc, long term & hidden. Then effects: social, economic. Then possible solutions: macro/micro. I think i've forgotten some (it has been 4mnths) but u get the idea (i hope).
If u gave an essay topic, it would be easier to assist.