Communications: Communications consultants specialize in helping employees in both large and small businesses better communicate with each other, which ultimately makes the business more efficient and operate smoothly.
Marketing: Can you help a business write a marketing plan? Or do you have ideas that you feel will help promote a business? If so, why not try your hand as a marketing consultant?
Business: Know how to help a business turn a profit? If you have a good business sense, then you'll do well as a business consultant. After computer consulting, people in this field are the next most sought after.