Once you have developed an argument you can fit it into a structure. This is the device which enables a reader to navigate easily around your text, to recognise what stage he or she is in within it. Again, there are no hard and fast rules about structure but there are various pointers which may help you to construct one. A structure within an academic piece of writing is a teleological beast: it has a beginning, a middle and an end, and all parts are aimed at the triumphant conclusion where the scholar can shout out ‘Q.E.D’ or alternatively, ‘there, you see, prove me wrong!’
So, briefly: you need an introduction, a substantive piece of argument, a recapitulation of that argument, and a conclusion.
Wherein you introduce your subject, enumerate the topics you are going to cover (in the order that they are to be covered), briefly allude to the points you are going to be making and pose the questions you set out to answer.
Substance (or middle):
Wherein you develop your argument point by careful point, providing evidence where needed.
Wherein you summarise the main points – a reader needs this sort of help when dealing with a lot of unfamiliar material.
Wherein you draw all the material together and point it in a particular direction, ready for the next chapter.