First, you will have to recognize that seeing opportunity is a step towards beyond success. When you are open to seeing opportunity, more will be presented towards you. Through experience you will spot out the good opportunity from the bad ones.
Second, spotting opportunity is easy but that does not mean that you will always see them. The best way to see opportunities, is positioning. You must position yourself in situations where opportunities are more likely to happen. Networking is key. Get in with the people in your field, attend seminars, join social networks, hang out with friends that are going the same direction you intend to go in.
Third, when you are positioning yourself around these events and people, you must be ready to ask the right questions. The right questions lead you to the answers you will need to seize the opportunity presented. I suggest practicing the questions beforehand that you want to ask, so you can be better prepared. Next once you get all the answers you need to move on, it is time to take action. Take the action and don't look back. This will bring you to your results. Before you know it, you will be in the position to ask these questions with confidence and taking full advantage of the opportunities that are presented to you.
(Steps taken from ehow.com)