Such humans include your instructor. Thus programs must be written in such a way that people can read, understand, modify, and have confidence in them. One of the goals of this class is to have its students develop good programming habits, and documentation is such a habit when done right. Part of the grade for this course is based on your programs' documentation and readability. Readability is part of your grade, so you must develop some style standards to make your code easy to read.
Clarity is more important than space.
The nature of your control structures. Above all, avoid random left margins. As part of this concept, variables used should be defined where they are used, so you should minimize your use of global variables.