Sitting down to really study is very important. In most of your classes, you will have two tests and a final as your only grades for the semester. If you bomb a test, that's one-third of your grade. Ultimately, you have to deal with the grades you get. Going to class and studying hard are very important, but it is understandable that all of us are going to screw up occasionally.
Distractions are so easy to come by, and often the freedom goes to our heads at first.
Just try to remember not to get too carried away because your grades really are important if you're looking to go any further. Hey, if they're good, often you get a few perks from Mom and Dad. College is refreshingly an entirely different world than high school, and that's great. It's more fun than most of you can probably imagine, but you are here having fun because Mom and Dad are paying the big bucks for you to study and get an education.