Good engineers write good code, but the best engineers raise the skills of their junior colleagues, too. If you’re a senior engineer, you must learn to mentor new hires. Especially if you’re committed to diversity: mentorship is critical to the careers of women and minorities in tech. I have failed at mentoring, then succeeded. I distinguished five warning signs that a mentorship will fail, and five prerequisites that make a mentorship very likely to succeed. Learn from me, and march to mentorship triumph.