Coming to college can be a difficult time to find some sort of balance of everything that has to be done. There's actual school work, extracurriculars, work, assessment preparations, the list goes on and on depending on who you are. Finding the balance amongst what is and isn't essential is a big key to being successful in your college endeavors.
One thing that I find essential for maintaining a balance is taking the time to plan: assignments, test preparation, extracurriculars, work, etc. Every Sunday I sit down and go through all my syllabi and calendars and write down dates in my planner, as well as a to-do list for what I want to get done over the weekend AND another to-do list of all my assignments/assessments for the upcoming week.
Tedious? Yes. Worth it? Big yes.
Another essential thing to do is to distinguish what is a priority for you personally. While it may seem intriguing to join all these new organizations on campus, it can easily become time-consuming and overwhelming. Take the time to consider what you really care about and what you really want to do. You can't do everything and do everything well. It definitely pays off to dedicate your time to what you really care about instead of being halfway in with a bunch of different things.
Finally, leave some time for yourself. You can use this for some me time, an assignment that came up unexpectedly, extra study time if you feel unprepared for a test, etc. Leave yourself some time so you have some wiggle room in your week for hiccups or some relaxation.
It's a challenge and a task to find the balance in life, but once you find it, it's totally worth the time and effort. You develop this perfectly nice schedule that pieces your day to day life together and honestly, it's wonderful!