Really liked the Ratatouille reference and I also think that it applies to this situation.
Regarding the second statement - how can you improve your eye for good or bad design? I would think that that particular skill was the one that meant you were cut out to be a designer.
Practice. Expose yourself to design work that others like. Collect examples of design you like. Eventually your brain can learn from a wide enough sample. Its improvable for anyone, but if you have an eye to begin with, you'll go a lot further because its easier.
Really liked the Ratatouille reference and I also think that it applies to this situation.
Regarding the second statement - how can you improve your eye for good or bad design? I would think that that particular skill was the one that meant you were cut out to be a designer.