Want to know a sure-fire way to get to know your son better? Interview him! You can ask serious questions, such as what is he most proud of in his life or what he might be afraid of. You can ask his favorite ice cream flavor at the moment or his favorite book. Or, you can get really silly and ask something like what animal would he most like to bring to school, or, if he could be any kind of toy, what would he be and why. Then, have your son ask you the same questions back.
Asking your child questions helps him realize your interest in him, and it'll allow him to open up to you and help him feel more comfortable expressing himself. Make it an annual, or even quarterly, event and see how his answers change over time. You may also be surprised at how he may want to ask you questions back, sparking his interest in you and the world around him.