The most important functions of the introduction are to state and narrow the topic of the essay. A secondary function of the introduction is to interest the reader. Also, it is in the introductory paragraph that the thesis sentence is placed. The best place to put it is as the last sentence of the introduction. One method of developing an introduction is to go from general to specific.
Baseball games are usually predictable.
Low budget films have overwhelmed the movie industry. An evening stroll in the park has become a mad dash for one's life. This is a good introduction to a description paper. Notice that the introduction announces a topic, limits it, and also creates interest. Another method of writing an introduction is by asking a question.