A well-focused thesis statement, key to organizing an essay, contains two elements: a precise subject and a precise restricting element.
Vague - Ecological disasters are a major concern today.
Precise - Pollution of underground water supplies threatens cities on the American West Coast.
Use a precise topic rather than a generalized topic when writing a thesis. Avoid statements like “I will use my essay to consider. . .” and “This paper will discuss….” Although there is no required position for the thesis in a multi-paragraph writing, normally it is located at the end of the introductory paragraph. It serves as a guide to both the reader and the writer.
A thesis should have the following characteristics:
*It should be simple or complex, never compound.
*It should be stated positively.
*It should be restricted, precise, and unified.
*It should not contain figurative language.
Your thesis statement makes your purpose clear from the beginning and sets up the arrangement of the text that follows.