Give away your trade secrets.
Designers at every level have a room to learn.
Each time you meet with a designer, combine specific feedback with one design lesson.
Specific feedback is stuff like: “move this button to left align with the form fields.” The design lesson might be: “use alignment and figure-ground relationships to create scan lines or visual funnels to bring the user’s eye down the page.”
Show your designer a couple of examples, then ask him to talk about how he might apply the lesson to his work. The next time you meet, hopefully he’s nailed the last lesson and you can the next one.
Convey a sense of purpose.
Motivate your designer by letting him know how his work fits into the larger vision the team is working toward. State the overall goal, but give him the freedom to innovate, experiment and take risks.
Ask questions to push his design thinking.
Give your designer a chance to think for himself and defend his ideas. Give praise and challenge. Say, “This is awesome, what other ideas did you have around this?” The more specific the praise is the more it helps him grow.
Instead of saying, “Move this button to the left,” try forming it as a question. “Can you tell me about the button placement on this page?” This gives your designer a chance to think for herself. Maybe she’ll have a great defense that pushes a product to be more innovative. Or maybe she’ll say something that you can turn into a teachable moment (pardon the cliché).
Be her career advocate.
Not only are you accountable for the work; you’re also helping guide careers. If you constantly find you’re giving feedback on the work, but not on the person, have another meeting where you’re talking about their growth, approach or attitude. Make sure you’re trying to give your designer project work that will help her grow.