The introduction should provide the setting for the paper, introduce the reader to the topic under investigation and provide at least a partial description of what is to come. It can be useful to also explain how you have structured your argument and the major steps in your research. It is not intended as a preliminary literature review, but should identify the main researchers and authors whose work defines the area under investigation.
The introduction may be one of the last things to be drafted, probably not the first, because you need to know what your paper contains before you can introduce it. There are four things that a good introduction can achieve. First, the opening sentence(s) should identify and justify the topic, explaining why it is important. This opening positions the work and makes clear what the topic is. Just because you have a title above this, it does not mean you can skip the opening. Second, it is useful to deal with the difficulties that are inherent in dealing with a topic of this kind. One useful thing to include is a discussion of the general class of problem of which your study is a specific example. This helps to position the work and make clear that you are not starting from scratch in your paper. You will be building on what has gone before, even if no one has ever studied your particular topic before. Also, it helps your reader to understand not only what you are doing, but also what you are not doing. Third, narrow down the topic to the particular arguments that will be advanced. This brings focus to the work and identify the contrasting views that make this topic contentious. Outline the main protagonists and tensions in the kind of issues that you will be dealing with. Finally, outline the structure of your argument. In describing the structure of the paper, it is important to do more than merely describe the headings used in the paper. A better approach is to explain how you have structured your argument and the major steps in your research. The purpose of describing the structure of the paper is to make clear the argument, rather than describing the headings. One common mistake in outlining the contents of a paper is to describe in general terms the elements of a typical paper. This is a rather uninformative approach. Instead, the outline should be informative about what the various sections of the paper actually say.
With these elements in your introduction, the reader will know what to expect from the paper and will be able to understand clearly what you have achieved. It is important to avoid using complex critiques of literature in the introduction. It is a significant opportunity to engage your readers and make clear what the paper is about.