If you're an expert who gives advice or offers professional consultations, you can call yourself an adviser.
You can have an adviser in many areas — he or she may also be called a consultant. A person who helps you decide what classes to take is called an academic adviser. You may also have a tax adviser to help during an audit or a career adviser to help plan your next steps after college. Whoever you take advice from, be advised that this word is sometimes spelled advisor.