Career tips for creators from 5 of Steve Jobs' friends, including Tim Cook, Jony Ive, and Bob Iger

Steve Jobs' signature look was a simple black turtleneck.

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• Steve Jobs' legacy was celebrated with letters from influential friends on what would be his 71st birthday.
• Apple CEO Tim Cook advised young creators to focus on who they will be, not just on future outcomes.
• Jony Ive emphasized Steve Jobs' focus on ideas and relentless curiosity in creative processes.

Late Apple cofounder Steve Jobs had a variety of powerful friends, and...