Time Management will be your key to success trust me. Do not procrastinate on your assignments because professors don't care if you have homework and stuff for other classes and if you wait to long to do your work it will build up really fast and will be really hard to get done. Also it is good to socialize and make new friends, but choose them wisely. Pick friends that will be there for you and help you in classes if you need it.
I'm a sophomore in college currently with a 4.0 gpa and all I gotta say is just have fun. But just put your responsibilities and work first before fun and you will have no problem.
