Construct an outline for your entire paper before writing your introduction so that you know where you are going and how you intend to get there. A logical outline will help you craft a logical introduction.
Introduce your topic. Do not give too many details; these will be provided in the body of the research paper. Just write a sentence or two to introduce the topic with a focus on building the reader's interest. This is your chance to capture the reader's attention and convince her to read your paper.
Present the specific area of your research. After you have introduced the general topic, focus the reader's attention on the specific area of the topic that will be addressed in your paper.
Add an interesting story, revealing statistic or compelling example to show your reader why the topic is important. This will further draw in the reader and convince her to read your body of supporting evidence.
Justify the model you used in your research. Provide your reasons for choosing that particular approach and list its advantages. For example, if you prove your points with heavy use of statistical data, justify this method by explaining how the data relates to your thesis statement.
Write your thesis statement, or hypothesis, as the last element of your introduction. It can usually be stated in a sentence or two.