Package design courses can be completed in most graphic design programs. The course content may include print standards and practices as well as real-world package design done by the students.
Books covering package design exist as both reference and instruction material. Look for books in color with high-quality photographs of packaging. Locate useful lists compiled on the topic online.
Check online or with AIGA, the professional association for design, to find out when and where package design training and conferences are being held. These daylong or weekend courses can be an excellent starting point as well as a way to supplement an existing understanding of the topic.
Additional educational material is available online as well as in print publications like Communication Arts. These semiannual publications provide valuable insight into current industry standards and trends.