The abstract is a short (about 100-500 word) summary of the entire paper. It should include: goals and objectives, results, and conclusions. It is usually one of the last parts of the paper to be written.
The introduction also has three main purposes. First, it provides background and motivation for your topic (usually includes a review of current literature on the topic). Second, it describes the focus and purpose of the paper you are writing. Third, it gives an overview of what is contained in the paper's various sections.
This section describes what you did, how you did it, gives strategies, sample calculations, diagrams and models, and descriptions of the process used to analyze the data. The goal here is to give the reader sufficient information to be able to repeat your work if desired. (Of course some "standard techniques" can be simply referenced).
This section is where you prove your point with the data. Give graphs and tables of costs, profits, whatever your data is. Also give some description or guide to help the reader recognize your important points.
Here you state what your learned or proved. What are the "take home messages" or major accomplishments of this work? You may also describe interesting observations, new questions, and future work here.
Present the sources used in paper/article in APA/ MLA Style with page Nos.