Sense of analysis: to well understand customer needs and expectations, even if he can't explain them clearly.
Shape feelings: Shape comes from material functions but also from identity that the product holds. It is necessary to use and control cognitive and cultural codes. The product have to "speak" by itself to users.
Technical skills: a designer is not an artist, he has to take care his projects are feasible. So he has to be conversant with indutrial processes, communication tools, material properties...
Business consciouness: a designer doesn't work alone, but for people, for customer and often for company, and it's a good point to be able to understand this complex total environment.
Intelligence: everytime the designer has to update his knowledge with marketing, design (all fields), technological, ... intelligence, to be able to include research data and improve his projects with it.
Ethic and personality: to be a designer is not a way to be famous, but it is necessary to spread like a signature, an emotional function inside a product.