There are several ways you can have an effect on oil conservation. First, when you are of voting agr, register to vote and make sure to vote for candidates who support green policies. Second, become actively involved in the political process by working for candidates who support green intiatives. Third, consider a career in which you can directly effect oil conservation, whether in green industries, media, or politics.
On a purely personal level, you can choose green options, walking or biking to school, car-pooling, eating locally sourced food, avoiding meat, choosing recycled/recyclable products, and generally working with your friends and family to create a sustainable lifestyle.
Consider forming a green committee at your school that can provide a way for you and your friends together to tackle conservation issues directly pertaining to the school such as setting up car pools, green-sourcing of supplies, increasing recycling, etc.