When you start professional years, you do get classes to help you understand what counseling consists of - how to greet a patient, what questions to ask, what signs to look for (posture, physical symptoms, etc). Then you apply it in lab scenarios (where your professors or 6th year students, or TA's are "patients"). Do you work in a pharmacy? The best place to learn how to counsel is to observe your pharmacist.
If you want a quick and dirty breakdown of how I would counsel, here:
1) Greet the person. Hi, how are you. How are you feeling?
2) Person usually tells you they're not feeling well. Ask them what's the problem, what are the symptoms, how long the problem has been. -- Because you haven't had pharmacy courses yet (or else you would have had a counseling-related class), this information wouldn't be too useful to you because you cannot determine if you can recommend OTC or send the person to the doctor.
3) Give a suggestion, if you can.
4) Wish them well, thank them for asking and coming to speak with you.
Pharmacy school makes you memorize facts, but you have to find ways to use it. It just takes a lot of practice to counsel smoothly.