I don’t think it matters how many or how few students you serve in your ministry. There just isn’t enough time in the day for you to give every one of them every thing each of them needs to be strong spiritually. Ministry can be like triage in a medical large scale emergency. Who needs help critically? Are some cases too far gone? Are “healthy” students without needs?
One of the ways you can triage your students spiritually is to look at each one separately. What strengths do they have in their spiritual walk? Are their parents actively teaching them about God and what He wants from them and for them at home? Do they have a vibrant prayer life and spend time in independent Bible study? Are they making consistently good choices? Or do they have little knowledge of scripture? Do they attend sporadically or seem disengaged when they do attend? Are they angry at God? Do they think they are smarter than God (whether they admit it or not)? Do they get little, if any, spiritual instruction at home? Do they make poor choices more consistently than good ones?
Once you have a pretty thorough picture of each student spiritually, it’s time to think through a spiritual growth plan for each. What resources, training, teaching, coaching, etc. would most help that young person grow spiritually? What are they currently getting at home or through your ministry? Star the things you think they are lacking that are the most critical.
Now look at those answers individually and for the group as a whole. Are there things your ministry can do that will be helpful to various groups of students? How can you help meet individual needs that would best be addressed one on one? What new volunteers do you need to help make sure every young person can get the help they need to grow spiritually? What training will those volunteers need?
This exercise can be even more helpful when you work on it as a ministry team. Asking students for their opinions on what they need can also be informative. It may not always be correct, but it can help you get a better understanding of where they think they are spiritually and what could help them grow. The exercise takes time, but for at risk students, it can make all of the difference in the world.