Unity is one of the best game engine that allows to you create amazing games, even alone. However, if you have serious intentions to create and promote yours games, probably you will be working in a team. For the team should be the roles of team members - but in any case the team must have a programmer who programs in Unity.
If you are a beginner and just think about the development of Unity, then some useful resources will help you to become a programming guru in the Unity, though not immediately.
- Unity3D tutorials
- Unity3D manual
- Unity3D community
- Unity Analytics
- Unity Getting Started with iOS Development
- Unity Getting Started with Android Development
- Apple Developer Site
- Google Android Developer site
- Build a Game Using Unity 3D by Michigan State University
- Online training by Unity
- Make a Multiplayer Shooter in Unity
- Creating a 2D Game in Unity 4.5
It is all free resources. Good luck in your endeavors.