Reflection is an essential part of learning. The better you become at reflecting, the more you will be able to guide your own learning. At first it can be hard to see the bigger picture. Being asked to reflect on your work when you don't know how good it is can feel frustrating. However, engaging in the process of reflection is the first step. The more you learn about your subject and yourself, the better you reflection will become.
In order to gain perspective, stand back from a situation and seek guidance through conversations and reading.