Having a good base of design should be is the starting point of any project. It is the basis of the pyramid of a good product.
First: Diferencial aspect.
The main idea is the first block of the base, and the most important is the question: What is the differential value in my design? We usually design because we have some necessity for cover, not for copy products, anyone can copy product better or cheaper than you.
You, as a good designer, have to add a new value, something that makes your design different of the rest of the designs.
Then: You must know clearly the differential value of your design.
Second: information and more information.
After this, the other important block of the pyramid is information. You have to give yourself tons of information. This is not a minor point because: Starting to design without enough information is a typical mistake.
Honestly, everyone prefers to design more than reading, we love the action and we hate reading, but the lack of information will be paid with a waste of time and money.
A bad design caused by the lack of information will cause many errors in the manufacturing process, which causes a waste of time, and potentially, the waste of materials.
A good product, is the result of a good design, and a good design is the result of a good idea well developed.