Usually this structure:
1, self-awareness; -the state of your habits and likes;
2. Post-cognition; -Collection and analysis of professional and post information of this major (or interested major);
3. Work plan;
4. Inspection and supervision of effective work.
Refer to the book "Meeting the Unknown Self" and "What color is your parachute".
If economic conditions permit, try to find a professional consulting agency nearby and complete the system planning under the guidance of professional consultants.