NACAC put together a comprehensive guide for students called "How to Use Your School Counselor," which you can view here. "Use" is actually a good term, because it's not your counselor's job to thrust unsolicited help and advice on you. The onus is on you to actually use the resource. Ask for help and you'll almost certainly get it.
Here are two past posts of mine here and here on how to build a good relationship with your counselor.