This strength keynote by Marcus Buckingham is a great way in which to decide what you want to do for a living. It offers a more effective way to decide which parts in your life are strengths and which parts are weaknesses.
Instead of being defined as things you are good or bad at, strengths are defined as something you enjoy doing and weaknesses as things you loathe doing. If you enjoy doing something, you will want to do it and can easily become better at it. This is the opposite with weakness as you will drag your feet and get distracted very easily.
Marcus’s strength keynote suggests carrying around a piece of paper that contains a table. The table should consist of the columns love and loathe. He says to place the things you don’t enjoy under loathe and the opposite under love. This table will then make up your strengths and weaknesses.