That's it! You now know how to use the jMonkeyEngine to develop a Java 3D game, you are aware of the most common pitfalls of game design, and you know the best practices for how to avoid them.
The Appendix B, Additional Resources for Fellow jMonkeys contain more information about the jMonkeyEngine SDK, how to set up the jMonkeyEngine without the SDK, and many links to game resources, where you can find free assets, tools, and tutorials.
Need help? Join the jmonkeyengine.org forum; you are always welcome to ask questions. And (interesting fact!) now that you've read this book, you are also qualified to answer questions!