The descriptive essay is a genre of essay that requires the student to examine an idea, evaluate the evidence, state an idea, and present an argument regarding that idea in a clear and concise way. This can be accomplished through comparison and contrast, definition, example, cause and effect analysis, etc.
Note : this genre is usually assigned as an assessment tool in the classroom and is often found in a variety of domyessay reviews formats.

The structure of a descriptive essay boils down to the following.
A clear, concise, and definite thesis statement that occurs in the first paragraph of the essay.
It is important that this statement be appropriately narrowed to follow the guidelines outlined in the assignment. If the student does not master this part of the essay, it will be quite difficult to compose an effective or persuasive essay.
Clear and logical transitions between the introduction, the foundation, and the conclusion.
Transitions are the mortar on which the essay is based. Without a logical development of thought, the reader will not be able to follow the argument of the essay, and the structure will collapse.
Body paragraphs that include evidentiary support.
Each paragraph should be limited to stating one general idea. This will ensure that the entire article is clear and focused. Moreover, this brevity creates ease of perception for the audience. It is important to note that each paragraph in the text of the essay should have some logical connection to the thesis in the first paragraph.
Evidentiary support (factual, logical, statistical, or anecdotal).
Often students are required to write expository essays with little or no preparation; therefore, such essays usually do not allow for much statistical or factual evidence.
A little creativity!
Although creativity and craftiness are not always associated with essay writing, it is nevertheless an art. Try not to get caught up in the formal nature of descriptive writing at the expense of writing something interesting. Remember that you may not be writing the next great novel, you are trying to leave a lasting impression on the people evaluating your essay.
A conclusion that doesn't just reiterate the thesis statement, but redefines it in light of the evidence presented.
It is at this point in the essay that students will inevitably begin to struggle. This is the part of the essay that will leave the most immediate impression on the reader's mind. Therefore, it must be effective and logical. Do not introduce new information in the conclusion; rather, synthesize and come to a conclusion regarding the information presented in the main body of the essay.

Related Resources:

The difference between an essay and a term paper
Structure of the essay
Descriptive essay - What is this?
Structural features of an academic essay