What are reflections? They are thoughts on some subject. These thoughts can be intensely personal based on personal individual experience. They can be the thoughts of a person who has undergone some trauma and the resultant sharing of lessons learnt from those experiences may be seen in this form of a reflective essay. It can also be the explanation of certain abstract concepts that have been elucidated with the help of examples. These thoughts can also be a collection of ideas from a group of people--say for example, a person can interview many refugees and write about their feelings after a war and intersperse his own thoughts and opinion. This would also be a reflective essay.
One can also write a reflective essay on some philosophical concepts or beliefs. The reflections can be on some social and political issues like the eradication of poverty, abolition of caste, child labor or child marriage.
How does one go about this reflective essay is the question that would loom large before the student. First and foremost, here there is not much scope for imagination and the student would have to compulsorily do a bit of research. He can seek guidance from essays written by eminent authors. He can also read through the reflections of other great people and get an idea. Whatever the theme is, it must be supported by facts and concrete evidence. There must be clarity in dealing with the theme. All statements must be well reasoned and there must be no scope for ambiguity. Download a few of the reflective essays from the academic library and get some ideas about this.