What you intend to classify may be something real or conceptual. To classify means you will have to make sense out of a potentially complex and confusing collection of things. This will also mean that you have to sort them out into categories that you can conveniently thrash out one at a time.
As soon as you begin to write, you should make sure that your classification is really easier first for you ahead of thinking about your readers. Remember that if it is complex for you, you will not be able to classify it to the understanding of the readers. When you classify, make sure that the divisions and categories that you have are sensible when read on their own and when the whole essay is read as a unified whole. It will be important if you start your classification from a general outlook to a particular approach. For example, if you are asked to classify the student population of your school, you should begin by separating it into males and females ahead of breaking them further into undergraduate and postgraduate students. You may further break them down into age groups, programs of study and so on.
In classifying, you should make sure that your language is simple and straight to the point. Remember that you will be making a complex situation simple in the minds of your readers. You will not achieve your purpose if the readers do not understand your essay. Your sentences should be simple and short. Your paragraphs should not be very long. However, if you have longer paragraphs, make sure that they are solid, stout and interesting to read. Avoid making general statements of repetitions of your points.
Classification essay should be properly revised and edited. Make sure you have used the most logical principles for classification; make sure that you stick to one and the same principle for classification throughout the whole of your essay. All the categories that have any similarities should be grouped together and these groupings should have an order in which they appear. It will also be important if you bring in examples. Make sure that any example you bring should be relevant and applicable to the point you are trying to make. Your examples should be the best and most recent examples and they should be very specific. Remember that most of the categories that you develop will be easier understood with illustrations. Finally, you should revise to make sure that what was considered as complex has been broken down to something simple. It is always advisable to hand your paper to some other person to read for understanding ahead of submitting it to your teacher.