Take your time; try to keep an eye both on details and on the bigger picture.
Look at something carefully, put it away, and then look at it again.
Organize brainstorming sessions.
Try to think outside the box.
Take a step back regularly from your daily routine.
Attempt to find several alternatives to a problem.
Draw your employee`s attention to new developments and ask for his opinion. Let him follow new trends. Ask him for alternatives.
Ask the employee to investigate developments and innovations.
Acquire sufficient information and know-how.