This totally depends on what course you are pursuing and what do you mean be a good student and this is quite a subjective question. Some of the major in general tips that I would like to give you are:

• Instead of counting hours be punctual.
• Set daily targets and no matter what happens, achieve them.
• Keep a performance metric that evaluates how good are you.
• Set a metric target that would satisfy you and never look back.
• Work super hard

If you follows these points, there is no reason why you won't be a good student!. Hope I have answered your question. All the best!

Hello,

This is a question for which every answer would vary if you ask to different persons. For me I don't think studying 15 hours a day would increase your efficiency instead you should focus on effectiveness because even if you study less you should be able to recall or implement what you have studied.

If you study for 15 hours and can remember nothing then it's not efficient enough.