This is the term for dissecting the development of past games and it is good practice to perform one on a game jam game you have just made. You can do this privately or publicly, which can always benefit others. You will need to analyze the game thoroughly and ask yourself some questions about what you've done.
What went wrong/right?
Did the game stay true to the initial idea?
Did others find it too hard/easy?
Was it balanced correctly?
Can you envision the gameplay being improved upon?
Were there any decisions you made early on which made development more difficult later?
There are many ways to look at a game jam game in retrospect but it always a good idea to keep in mind the reactions/feedback of others that played the game. This will help you make better design decisions in future.
And that's it. Congratulations! You have completed your first Game Jam! I'm sure you are so much wiser now because of it.
Whats next? Well this is up to you. There are game jams happening all the time nowadays so you can increase your skills further by doing more. Or maybe the team you worked with want to work on something together, perhaps a long term project? Or maybe you like your game jam game so much you want to see where you can go with it by developing further.
I feel Game Jams provide the perfect kick starter method for any aspiring game developer to get into the industry, whether its triple A or Indie. Game Jams can fill your portfolio and demonstrate to others what your capable of. The advantages out way the difficulties you may come across when starting out in my opinion.