Which course should I prefer in the CUSAT with a rank of 1,500 (general), and what courses are better in the CUSAT?

Before enrolling yourself in any course, learn about your passion first. Research about the engineering stream and its various aspects. You can also talk to your elders to know about your interest. If you are passionate about it then only get into the engineering field.

CSE, CE, EEE, ME are considered good at CUSAT. But the placement of Safety and Fire Engineering, CSE, IT, EC is better. Other departments of CUSAT often have an off-campus placement or go for GATE.

These are some good departments at Cochin University of Science and Technology (CUSAT)

1. Civil Engineering: Total Batch Intake 90 students
2. Information Technology: Total Batch Intake 90 students
3. Computer Science and Engineering: Total Batch Intake 90 students
4. Mechanical Engineering: Total Batch Intake 90 students
5. Electrical and Electronics Engineering: Total Batch Intake 60 students
6. Electronics and Communication Engineering: Total Batch Intake 90 students 
7. Safety and Fire Engineering: Total Batch Intake 60 students

Therefore, CUSAT has several best departments and courses. And if you are thinking of joining it, then you must go for it. But do not forget to know about passion first.