I noticed that there are really few posts about package design. I found this simple Adobe Illustrator tutorial from Layers Magazine.

"Companies must often begin promoting their products before they’re actually produced. One way to promote goods before they’re completed is to generate the package art and create a 3D box shot.

Now this is something we see all the time. In fact, just recently this was prominent on the Adobe website where they had all the Creative Suite box shots displayed. We’ve also seen it used on the Apple website for a lot of their products. So let’s create our own virtual box shot in Illustrator." Full Tutorial