Listen to the teacher. Do all your homework. Work hard.
P.S- you should really be studying
Here are some good links you can look through, too!
Simple - YOU DONT !!! Work hard - get your grades - go to college - get a good job - enjoy a good life There is no short cut. But here are some good links to help you get better grades!
Studying hard, doing all of your homework, do extra credit, working hard, etc. improve after and repeat
I believe studying helps me get good grades.
getting good grades
study for the next test and get an A+ on it which will raise your grade
You can take a cerent test or get good grades
Of course A plus is a good grade its probably one of the best grades you can get!
The only way you can get A's in school without studying would be cheating on all your exams. Cheating is never good as the only person you are cheating is yourself because you are not learning just getting the good grades. In the long run it will hurt you more than help you.
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. 
According to me, getting good grades do not affect how much you study. I basically just, well, study a lot even though I get As and Bs all the time. That's a good example of how studying all the time gets you good grades! You have the right idea about studying. I think the question is asking the opposite, though. Oddly enough, getting good grades too easily can affect your study habits. If your schoolwork is too easy for you, you might get into the habit of "coasting" or not studying much. Then, when you get into a higher grade, or into university, you will have poor study habits and your grades might drop. School should be hard enough for you to have to work to get the top grades - if you're in a class that's not challenging for you, ask the teachers and your parents about moving up to a more advanced class. Not only will you learn more, you'll be much less bored and you will be on the fast track for a university degree!
Of course you need to have good grades... as much as possible don't have grades below 85% . That's the standard grade you need to have to be able to get into the military. :)
becaz they study a lot and get good grades