Start by researching different careers, what they involve and the entry requirements. Talk to family, friends, and teachers.
Many careers will be open to graduates of any degree discipline while others may require a certain degree or further qualification.
Ask yourself:
Would I enjoy doing this kind of work?
Do I need a specific degree/qualification to do it?
What skills are required for the job?
Do I need relevant work experience?
Target jobs and Prospects are useful resources to help you get a better understanding of day-to-day responsibilities, qualifications, and skills required.
The icould website has some useful career videos to inspire you.
The National Careers Service is a fantastic resource to help with your research.