It just takes time and hard work. Those who make this much have high quality hubs and informative hubs. Just think of what people need to know about. Subject and quality is two things you need. Some people right hubs just to add another notch on the list. Make sure they are high quality, with pictures, very useful, and easy to find the main points of the subject. More hubs, more earnings potential. Just make them the best they can be.