Grades are the most important part which proves our capability, analyse our mind skills and also a type of so called report card which tells about our education. This is just the protocol that has been following up from decades. 

It is also crucial to get the good grades to open more and more ways for your success.

There are some of the ways we can improve them - 

1. Foremost rule - Study - Obviously the first step without which nothing can happen.
2. Take breaks - Break for 5-10 minutes is more than enough after studying continously for 45  minutes or 1 hour.
3. Make flash cards - This keeps you connected to fun also.
4. Get someone who can take your quiz - This will help you to evaluate yourself that how much how are prepared.
5. Give yourself short treats - Keep a snack or drink around yourself while studying  and definately not that heavy meal which will obviously make you sleep after having that but just a light crunchie snack.
6. Music - Music can help many people but there are few who can't concentrate while listening to music. This keeps you active.
7. Take mock tests - It helps you to write up the answer at the time of examination. Try not to repeat the question while taking mock test.
8. Be organised - Everything should be correctly placed so that you may not miss anything important. All the notes, registers, stationary should be well organised to prevent them from missing away.
9. Be positive - Do not allow your thoughts to pull you aback. Be optimistic and think only to score good. Never underestimate yourself. Have faith in yourself.
10. Stay hydrated - water is the most important drink of our life. Always be hydrated to keep yourself active and to prevent yourself to take a power nap while studying.
11. Go slow - Never study in hurry. This can ruin your status of studying. You will think that you are learning everything but you may forget things easily too. Its important to retain the things in your mind.
12. Speak loudly or write - There are two ways of retaining the subject matter. Firstly you can speak it loudly again and again until you understand it or learn it in a better way. Secondly, you can write it again for 2-3 times. This can be time consuming but this will make you retain things more quickly