Hard work affects everything you do. If you are willing to work harder, then you will get better results. Check out some of the other Learning Tips questions for more information.
Some people are very smart but very lazy. You could be smart, but if you aren't willing to put effort into your homework and studying, you won't do as well. Often it is the people with some smarts and a willingness to work at school that do better than those people with more smarts and a sense of laziness. So yes, someone's amount of hard work can really influence their grades.
http://www.wikihow.com/Get-Good-Grades-With-Effort
duh! The more effort you put into something, the better it will turn out! I'm doing a research project on this and so far, all the sources say that a good attitude is the way to go. If you don't want to change your attitude, try getting more sleep. studys show that it's easier with a good night's sleep and some food, plus you operate better. You obviously don't have to listen to a kid like me, but it sounded like you could use some help.
Work very hard.
work and study hard
To improve your grades in two weeks you need to work hard and work smart.
You study really hard and work hard.
no
No, you will just have to work hard to raise that GPA.
Your grades should not be afected by having a detention. However, if you use detention time wisely and do school work or study, your grades may improve.
in higher grades there is more hard work
Yes,5th graders can get good grades. All you have to do is work hard and study. Plus, if you remember stuff for tests, hopefully you'll get a good grade. 
wel that depends on how hard you work and how high your grades are
there is no difference just grades and hard work
You can avoid it by studying and listening to the teacher. You should also work hard.