The use of templates to format your art for licensing has become a bit of a controversial issue. Some manufacturors say they are tired of seeing mediocre art slapped onto a template for a presentation, but I think the real issue there is the "mediocre" art! The fact is, some clients need you to format your work in this way. They have a set group of products that they need you to illustrate, and these cannot deviate in size or shape, due to the manufacturing process. You will gradually accumulate specific templates from your clients, and general ones can be purchased (check out Phyllis Dobbs' blog for this).
However, some clients aren't constrained by specific product shapes, and that is where product design comes in. I am just starting to try product design, and boy, is it fun! You have to have a certain knowledge of the manufacturing process, so you know which shapes are easy to reproduce (here's a hint: rounded shapes are easier than sharp, cut-in angles). Other than that, the sky, and your imagination, is the limit! Research your client's current line. You want to propose both versions of products they already make, and offer brand new ones that they haven't thought of yet. So now I'd better quit blogging and get back to the drawing board. Hooray!