Here are some useful tips and tricks for Unity3D in easy to understand form of animated gif. Initially I made a post on a Unity3D subreddit, and then some users chimed in with other tricks, so I added those as well.
Showing private variables in inspector.
Adding multiple prefabs in component’s list in the editor. Note: will not maintain order of items
Removing empty entry from an array
Making empty gameobject visible only in editor
Dealing with parenting and scrolling
Showing gizmos, colliders and raycasts (with Debug.DrawRay) IN GAME WINDOW while in play mode, works for selected objects only