I recommend the following "Key Word Editing" approach, drawn from Linda Flower's Problem Solving Strategies for Writing to decrease wordiness and achieve concise prose.
Key word editing simply asks you to focus on the important subjects and verbs in a sentence.
It is important to have the ability to prevent a student from continuing to utilize services that add charges to the student's account when that student is seriously delinquent in paying for the outstanding student charges. (36 words)
Students with delinquent accounts should not be able to charge additional services to their accounts. (15 words)
This sentence is not quite right. It doesn't say anything about preventing charges. Let's try another revision:
We need a system to stop students with delinquent accounts from using services that will increase their debt. (18 words)
The second revision is better. The sentence could probably be improved further. What would you change?