As you requires I am here giving you tips for preparation for scientist / Engineer (SC) Exam of Indian Space Research Organisation (ISRO).

Tips for preparation for scientist / Engineer (SC) Exam:

Know the syllabus of exam .

List out all subjects and start preparing according to weightage of marks

Use good reference books for preparation .

Solve last year papers .

Clear basics .

Give time for revision

Things to Avoid :
Tension
Confusion
Don't attend the question you don't know the correct answer

ISRO Scientist Exam Syllabus:

ISRO Electronics Engineering Syllabus
Electronics and Communication Engineering.
Networks.
Electronic Devices.
Analog Circuits.
Digital circuits.
Signals and Systems.
Control Systems.
Communications.
Electromagnetics.

ISRO Mechanical Engineering Syllabus
Applied Mechanics and Design.
Engineering Mechanics.
Strength of Materials.
Theory of Machines.
Vibrations.
Design.
Fluid Mechanics and Thermal Sciences.
Heat-Transfer.
Thermodynamics.
Applications.
Manufacturing and Industrial Engineering.
Engineering Materials.
Metal Casting.
Forming.
Joining.
Machining and Machine Tool Operations.
Metrology and Inspection.
Computer Integrated Manufacturing.
Production Planning and Control.
Inventory Control.
Operations Research.

ISRO Computer Science Engineering Syllabus
Operating System.
Digital Logic.
Compiler Design.
Programming and Data Structures.
Computer Organization and Architecture.
Web Technologies.
Theory of Computation.
Computer Networks.
Algorithms.
Databases.
Information Systems and Software Engineering etc.