The most important aspect is your knowledge and understanding. If you are satisfied with the level of your knowledge on a certain subject, hen you can safely consider it as the topic for your essay writing. But this alone will not take you far.

Now that you have got a clear idea of the subject, you have to spend some time thinking over it. If the subject is of a narrative or imaginative category, try to visualize the scenes. If the subject is of a reflective or argumentative category, try to think about the subject from various angles – personal, psychological, historical, political, economic, social etc. Try to recollect what your teachers, friends, parents, books or newspapers said about the subject.

Select the relevant material Once you have collected enough material for your composition, think over it again and select those points that are relevant and useful in writing the essay. Organize these ideas or points in a logical order.