There are several formal models of reflection that you can use to help you structure your reflective writing. Gibbs (1988) reflective cycle is a common model used in health and social care. However, you will probably be aware of others namely, Kolb and Schon.
Click here to see a Reflective Writing Learning Object
This learning object introduces a number of reflective learning theorists, and also provides you with some useful tips for reflective writing. It may be useful to try out different models and when your confidence grows adapt these to suit your personal style and needs.
Gibbs G (1988) Learning by Doing: A guide to teaching and learning methods. Further Education Unit. Oxford Polytechnic: Oxford.