The description of a case in which an experienced co-designed with a student (Donald Schön, 1984) changed how we saw design and design cognition. It changed from an overly scientific, or rationalistic process, to a practice-based and explorative approach. In this approach, framing, doing experiments, and reflecting on outcomes became central. Schön named his book  'The reflective practitioner' because having reflection capabilities is key for professionals.  

Also, for design thinking reflection is crucial. Even more so in the process of learning design thinking; designers are genuine reflective practitioners. Every stage in the process requires reflection. This applies to the discovery stage as well.
So, before moving to the next stage, take some time to reflect on: 

• Outcomes
  What results surprised you and why?
  What did you learn about the people you design for?
  What did you learn about the problematic situation?
  What frames did (implicitly) manifest themselves?
  Do you need to adjust the preliminary research questions/design-scope?
  
  
• Process
  What methods did you choose and for what reason?
  What were surprises and what did you learn from these surprises?
  What went well, what went wrong?
  How can you improve that?
  Did it deliver what you expected/needed?
  
  
• Personal growth
  What were your goals and what did you learn?
  What was difficult for you to do and why?
  What helped you, what did not?
  What do you need to improve?