Best practices for notebook information density?

There are high-density scribblings (think Mentaculus in A Serious Man) and low-density scribblings (think “Will not be graded by number of pages.” when actually “Teacher is damn lying lire telling lies.”) If there is no one to show your scribbling to which is most productive? Does larger or smaller page size help? How about college vs wide rule vs graph paper vs blank vs…?