1 - Answering the question.
2 - Report format keeps things easy for the marker to find. (e.g. subheadings for points discussed).
3 - Referring to key words in the question and keep coming back to them, keep information related.
4 - Use diagrams to explain points (when applicable) - this is a must as it shows you understand the relative economic theory.
5 - Keep up to date with statistics, use them to support your response and use only necessary ones.
6 - Define key words you're discussing in your body paragraphs at the start. (E.g. - the response is on inflation, therefore I'd define inflation).
7 - Anaylsing.
8 - Creating a fluent response. Practice by finding questions either past or making them from the 'learn to's', and dissect them do a little scaffold.
9 - Utilize your teacher - hand in practices and take on board feedback and ask them questions.
Check this out as well.
http://community.boredofstudies.org/22/economics/323700/long-response.html
Also the sticky threads at the top of the economics forum.
I hope I helped to some extent..