An art essay is not different in any radical way to any other type of essay you might already have worked on. However, these essays have certain specific elements. Every essay has to have a structure. Sometimes, this is very clear or it might be minimal and obscure, but it certainly will exist. The first step is familiarizing yourself with all the ideas and terms concerning the chosen art and being able to use these in the correct manner. This is the key to gaining an understanding of a work of art as well as mastering the art of essay writing.
Half your work is done once you choose an art essay topic. This should be intriguing to get readers interested. On a final note, if it is the case that sculpture, for example, enchants you, do not choose it if it is something you have not previously dealt with. The process of art essay writing is a lot easier if you choose to write about an aspect of art you at least know a little about. Otherwise, it will mean you have to learn about a particular type of art from the very beginning.
Whether you already know how to write an art essay or are just learning, do keep in mind that writing an essay, like any type of craft, has some requirements and standards that need to be adhered to. Despite this unsurprising limitation, however, writing an essay about art should prove easy enough provided the topic you choose is one you are familiar with and find interesting. Your desire to learn about a topic or subject that interests you will help you come up with original ideas and supporting evidence.