This 24 mark essay requires you to not only write a balanced essay, but also come to a judgement evaluated on the basis on evidence you have presented in your argument. This means it is key to both have an introduction/conclusion that is brief yet comes to a clear judgement, as well as organised points with well selected pieces of evidence. Getting the hang of the structure is easy once you have the hang of it, but can make a huge difference between getting a top grade and a middling one. Of course the most important thing of all, is to answer the question - one must specifically refer to Louis and his aims throughout the question.
In this case, in the introduction one may refer to Louis' desire to: secure his borders, weaken the Hapsburgs, and conquer further foreign territories. By 1685 he had largely achieved this, but at a social and economic cost - this is where one's own evaluative judgement is important. Whether progressing the essay through his aims and their success thematically, or over two sides, it is vital that each point made must be backed up with 2/3 points of evidence that backs up your argument. It is no use saying simply that Louis strengthened his borders through military reorganisation - give examples of the 17th century star forts that anchored his borders in the east that were built, or the modernisation of his foundries. At the end of each paragraph, pause and reflect on how this links to the question - if the evidence can be doubted or is not as important as other arguments, say so as this shows judgement and independent evaluation. The examiners do not want you to simply regurgitate facts at them. In this case one may come to the judgement that short term territorial gains were made by Louis at the expense of long term plans, as France was left diplomatically isolated, economically damaged and politically vulnerable. This one would put in the conclusion. as one comes to a clear judgement of what the the answer to the question is - there is no point in writing and argument if you do not provide an answer!