2. (No matter what I do, I cannot achieve my son's stature of 6'5", since I start out at 5'7". I could stand up straighter, wear clothes that emphasized height, maybe even elevator shoes (Adler Elevator Shoes were surely available once and may still be available), and I can buy the right clothing at Jimmy Au's. But none of that will make me look even close to 6'5. No matter what I do, I am unlikely to achieve an A in a graduate course in algebraic geometry, either, and probably not in a course in Torts or Contracts. Talent and aptitude are differentially distributed.
(As for your GPA and getting into law school or wherever: The best way of getting a leg up in the admissions world is for you to have good grades and lots of relevant experience. So if you want to become a dentist, perhaps you can work in a dental office. A lawyer, maybe even office work at a law firm, etc. Then there is a sense of your purposefulness and there is a chance that someone in the profession or field can write a letter of reference for you that is informed by their experience of your performance.
(One last point. In no sense has many a university been considered a nationally-ranked university prior to the previous 30 years, although each has grown and improved significantly in that period so that its prestige and ranking are much stronger now. Yet its earlier graduates, whose grades may not have been stellar, have gone on to distinguished careers. The campus and the distinguished professors you encounter are a consequence of their generosity. )
3. I appreciate you kind words, such as "I hope you have had a good weekend," or that your Hanukkah was good, or your ..., but that does not help you when you ask for something. It is much better to be direct. If you are in some difficult situation why not write something like,
Dear Professor Krieger,
I am being forced into marriage by my parents, and my psoriasis has flared up. Might I have an extension of one week for handing in the work.
OR I screwed up, overslept, and missed a crucial deadline. I will get the work in tomorrow.
OR It is hard to believe, but three of my grandparents are in different hospitals. I am close to all of them. I will need a two-day extension.
By the way, most successful people rarely ask for favors. Rather they extend favors to others, so that when they really need a favor it is a matter of others owing you rather than you owing them. Very powerful people are in a different realm.
4. And, by the way, showing up in class, participating, showing up on time, is actually noticed by instructors even if they do not take attendance and the class is large. If you are regularly late, or if you show up infrequently, and do not appear before holidays and the like, you become a stranger--and when you want a favor you are pressing your luck. People who show up, on time, participate, and in general are good academic citizens, will find that the world is more likely to grant their special requests. None of this need affect your grade directly, but the question always being asked is whether the professor could trust you with a major task. You often act as if you are anonymous and not noticed. And perhaps that is the case. But in a class of 45 students that is only rarely the case. And students who are good citizens are noted in conversations among faculty.
Put differently, you are always being noticed, watched, evaluated. Even at a large university.