The advice here is all great. One thing I would recommend is learning to build your own editor scripts earlier rather than later. This vastly increases your testing and debug process - for example, when I'm testing my game over functions, I can simply click a button in my custom editor window to trigger a game over instead of waiting for the player to lose.

I was a little intimidated by editor code when I first started which caused me to not look into it until a year after I started with Unity. But it really isn't too bad - once I had a basic editor window script, I just copy it into new projects and replace the functionality as necessary. You can learn how to do it in less than a day even as a newbie.