Summarize this article in one sentence.
Grading can vary wildly, depending on the subject, college, teacher, and the country you are in. However, a good quality program will have standards that both staff and students adhere to. The professors access the quality of your work based on certain criteria, which should be made clear at the beginning of the course. This does not mean that no appeal is possible, but by and large your responsibility is to meet the standard.  Unless the professor made a glaring error while grading your assignment or determining your course grade, they are unlikely to change your grade. It is also important to remember that grades are earned, not given. You do not earn a grade based on how hard you work, but rather how well you have mastered the material and followed the guidelines for the assignments. Unfortunately, you do not get bonus points for effort. In most cases, it is not worth your time or energy to attempt to get a professor to change your grade. The process will suck up valuable time, which can be better spent on future assignments and your other coursework. Before approaching your professor, think about whether it is worth the hassle. It’s important that you go over the course syllabus in detail before approaching your professor about the grade you earned. Carefully read every word of the syllabus, paying specific attention to the sections on assignments and how your grade is calculated.  For example, if you turned in the assignment late, you should consult the syllabus about the professor’s late assignment policy. This might explain why you earned a particular grade. This will also indicate to your professor that you read instructions and are thorough. You don't look great when the answer to your question is in bold in the syllabus! Before you approach a professor about changing your grade, you need to make sure you followed instructions for the assignment in question. Look over the assignment instructions and carefully consider each part of them. Not following instructions is often the reason you did not earn the grade you expected. For example, if the assignment instructions say to turn in a 5-page paper and you only turned in 2 pages, it might explain your grade.

Summary:
Understand the grading process. Decide if it’s worth your time and energy. Review the course syllabus. Make sure you followed the assignment instructions.