At its heart, GitHub is a platform for communication. Communicating in issues and pull requests is greatly aided by the use of Markdown. Take this course on GitHub Learning Lab to find out more about communicating with Markdown.
In case you haven't heard, GitHub has released GitHub Learning Lab: a new tool to help you learn GitHub...using GitHub! Go through guided courses on various topics and improve your skills at your own pace.
Check out the Communicating using Markdown course today.
For more information and to find other GitHub Learning Lab courses, check out https://lab.github.com/courses.
Find yourself stuck while taking a GitHub Learning Lab course, and need to talk to a real person? Get help in the GitHub Learning Lab Community Forum board.