Similar to my "How to be a Better Junior Developer" talk, with some new content, including incorporating my "Ask vs. Guess Cultures" talk.
Most developers focus on increasing their technical knowledge. However, there are many aspects to working as a professional developer besides coding proficiency. If you have interests or experience in other fields, you can pull in even those non-technical skills (like building relationships, project management) and immediately increase your impact on a project or team. When you mentor someone, you can help them play to their strengths and ramp up more quickly as a result.
Presented at ArrrrCamp 2014 in Belgium, ~30 minutes: http://youtu.be/u-LS1hMdSg4
Blog post: http://kwugirl.blogspot.com/2014/11/be-better-developer-no-code-required.html