There are no hard and fast rules for achieving success in design, but there are principles of good practice. Here are some of my feelings on the subject, some thoughts and observations ranging from A to Z:
Aesthetics. How something looks is always important. This does not mean that it has to be a work of art, just that it should look appropriate to its function.
Bugs. It is always better to assume that a design contains a bug than to believe that it does not. A designer should never check a design without having a supply of insecticide handy.
Constraints. There should always be strings attached to a design idea; they keep it from floating off into irrelevance.
Design. This is the most creative and most fundamental aspect of engineering. Other engineering activities, including engineering science, should be in service to design.
Economics. The self-made American engineer Arthur M. Wellington (1847-1895), in his book on the economic theory of the location of railways, defined engineering as "the art of doing well with one dollar, which any bungler can do with two after a fashion."
Failure. This thing that designers want most to avoid should always be first and foremost in their mind. Otherwise, how could they design against it?
Glass Part Full. It has been said that engineers view a partly filled glass neither as optimists nor as pessimists: They simply see the glass as improperly designed.