Below the title, name and affiliation the paper is typically structured as follows:

Abstract

A brief description of what the paper is about and its main contributions


Introduction

The problem is stated in a general way, motivated and put into context. 
This is where usually most of the references go. 
At the end of the introduction there should be a brief review of the 
following sections so the reader knows what to expect.


Problem Formulation

The problem is stated in detail and notation is introduced. 
The approach is outlined.


The Approach

Details of the method, with proofs if necessary.


Experiments

Experimental setup and results


Conclusion

Once more praise your achievements


References


[Of course you may deviate from this structure. But only in the middle.
Abstract, Introduction, Conclusion and References must come at these places!]