You can author your README using Visual Studio Code. Here are some useful editor keyboard shortcuts:

• Split the editor (Cmd+\ on macOS or Ctrl+\ on Windows and Linux).
• Toggle preview (Shift+Cmd+V on macOS or Shift+Ctrl+V on Windows and Linux).
• Press Ctrl+Space (Windows, Linux, macOS) to see a list of Markdown snippets.

• Visual Studio Code's Markdown Support
• Markdown Syntax Reference

Enjoy!