What are the principles a student should follow to start studying better than he does?

In Ancient India, the criteria that a student was asked upon to develop within himself have been discussed in this shloka:

काक चेष्टा, बको ध्यानं, श्वान निद्रा तथैव च ।

अल्पहारी, गृहत्यागी, विद्यार्थी पंच लक्षणं ॥ 

kaak chesta, bako dhyanam, shwaan nidraa tathaiva cha,

alpahaari, griha tyaagi, vidyarthi pancha lakshanam.

This shloka says that, "perseverance like a crow concentration like a heron, sleep like a dog, eating little food, leaving home, are the five signs of a good student."

Why does this shloka says that? Perseverance like a crow means just like a crow is perseverant to achieve its goals, a student should also be perseverant like that crow. Concentration like a heron means just like the heron stands still and concentrated in the water and once the fish comes near that heron, it immediately gulps over that fish and satisfies its hunger. Eating little food means that a student eats less food to concentrate better on his studies. Leaving home means that a student does not fear leaving home to gain knowledge. 

These are the five signs of a good student. If you actually want to gain knowledge, then you can use this method. Of course, this doesn't mean that you try so much that you get exhausted, or concentrate so much that your lifestyle becomes hectic, don't sleep enough so that you don't rest enough, or you don't eat enough food and start suffering from malnutrition. But this shloka tries to tell that if you slowly incorporate these characteristics within you then you will be able to become a good student. 

Anything and everything about becoming a good student is discussed in this shloka. Now the question comes, how can you incorporate these disciplines in you to become a good student? The answer is being consistent and disciplined. If you become disciplined, then you will automatically show these criteria in you and you will be able to become a good student, and do something even without the guidance of a good teacher. 

In Ancient India, this was the system of education of children and so the people that came out were very intelligent and disciplined. Today too we need to learn lessons from this shloka and even if you incorporate these skills at some and a very small extent, then you will be able to notice a vast change in your performance. 

I have also personally observed this happening with me. When I was in my primary school, then I was good at studies but I was not good at concentration because I did not know the importance of perseverance and concentration. But since I have passed my grade 6th, I have tried to incorporate these skills within me and I have noticed a vast difference in my performance.

Another thing is that percentage and marks don't matter at all when it comes to tracking your progress. Of course, they are important when you need to pass a class and enter in the next one, but their job starts and end just there. But for the whole year, knowledge is what matters.

Many of our relatives tell us to get good marks. "Why have you scored 85%? Why don't you score above 95% in your exams?" is a very common complaints that we students get to hear from our teachers, and our relatives. 

This suggestion is very good, and I agree with this. You should score above 95%, but if you can't retain that knowledge of that 95%, then what's the point in getting those high marks? They are just an empty golden box. A student who goes for the marks only gets the golden box, but a student who goes for both the marks and the knowledge gets not only a golden box, but that box is full of diamonds and precious jewels called knowledge and experience. Now it's up to you if you just want to get the golden box or the golden box full of diamonds and other precious gems.

Never judge yourself based on your marks. When you complete your chapter, ask yourself, "Did I learn something new from this chapter and how can I improve on the learnings of this chapter?" If you get the answer as yes, then go ahead and study the next chapter. If you get the answer no, then again read that chapter and then again ask yourself this question. This will make you a self-analyzer and being a self-analyzer is vital when it comes to increasing knowledge.