Understand the assignment. A reflective essay is an essay that asks you to consider or think back upon an experience. In other words you are "reflecting" or looking back on an incident or event and thinking about what you learned from it.
Brainstorm a list of topics or ideas. A reflective essay must be about something that you can look back on or think about and comment on. This can be an experience that you learned from. It can also be an event that you now perceive differently. The point is, you must "reflect back" or describe something that occurred, and how that occurrence or event has made an impact on you.
Select a topic about which you can provide considerable evaluation or information. Unlike a narrative or informative essay, you are not simply telling a story about something that happened in your life. You aren't recounting events or presenting an account of a past action. You are reflecting on or thinking about and evaluating those events. This difference is similar to the difference between a book report and an analytical paper--in a book report you simply tell what the book was about, while in a paper analyzing the book, you think about what it meant. With a reflective essay, you are doing this same type of analysis, only you are analyzing something that happened to you instead of something that happened in a book.
Outline your paper. Discuss what you want to talk about in each paragraph. Ensure that ideas flow together and that the paper has a thesis. The thesis should be your evaluation of the situation or the lessons learned from the experience. In other words, the thesis must show exactly what you are reflecting on. Each of the body paragraphs should support that main thesis and/or provide evidence or additional details about the situation and your reflections on it.
Write your essay. Keep in mind all of the considerations you evaluated when selecting a topic and making an outline. Your paper should smoothly flow form an introduction, to a description of whatever you are reflecting about, to your thoughts, reflections and evaluations of the situation or event that occurred.