Make all the "A's" you can make the first couple of years. dont' goof off and get those C's , D's and F's, save those for your harder classes, just in case.
Word of advice. Don't take anything for granted. Have an organized way of study and take a positive approach to classes and learning and make the highest grade you can make in classes instead of just 'getting by'.
Don't take anything for granted. Every grade count and you don't want to blow off an easy class and later look back and regret that if you make a better grade in this one class, you could have improve your GPA by this much more.