Create a pattern, know your strengths and weaknesses, and you'll be able to balance both perfectly.
I have been a full-time student for about three years and while at it, worked at my part-time job for about two and a half years. Juggling both work and school has never been easy and sometimes trying to balance them will be really hard at first, but here are some tips that can help you balance both without making either of them suffer.
1. Know what your priority is
You should have a list of what matters more to you, obviously as a full-time student, getting those As is your top priority. You have to know what your work limits are, that is, the hours you can work that wouldn't affect your academic life. You also have to know what your strengths are, know what part of the day you study better in. For example, if you study better at night, you can create a work schedule where you work mornings.
2. Have a planner
I invested in one at the beginning of the semester and it really helped me. It helped me plan my work and school schedule for up the month and through this, I got to know what my week would be like and predict if there would be a chance of my academic and work life clashing.
3. Know when to ask for help
Some days you would have to miss work for school and this can hurt your paycheck, which in turn will affect the bills you have to pay. This is when you have to know when to ask your parents or older siblings (if you have one) for help. I know we college students like to pride ourselves as independent, but it's important to know that no man is an island and you'll have to ask for help at some point.
4. Make time for rest
Working and schooling means most of your time will be filled doing something. Working always and not resting means that you will be stressed most of the time and at some point, you would break and it will hurt your academics. Create at least an hour a day to just take a nap, read a book or just to hang out with a friend.
5. Do your assignments on time
There is little to no room for procrastination when you have both a part-time job and school work. Like I said earlier, your days will be filled with either school or work, so you don't want to post-pone all your assignments till the day before its due thereby stressing yourself and putting out average work.
6. Reduce distractions
This can be sad to hear but watching a re-run of "The Office" can wait till the end of the semester. You have to realize that some sacrifices have to be made if you want to stay ahead of your class while also working. You might not get to party as hard as your friends because you have to work the next day but keep in mind that you're investing most of your time so that neither your grades nor work will suffer.
Working and studying full-time might be hard at first but if you know what works best for you and create a pattern, neither of your work life nor academic life will suffer.