Effective methodology for ISRO preparation ?

Preparing for ISRO exam requires knowledge of all basic fundamentals of important technical subjects of undergraduate course..
What is the syllabus for ISRO Scientist/Engineer (SC) exam?
There is no pre-defined syllabus for the examination.
However from previous year question paper’s analysis we can infer that Syllabus is based on the curriculum taught in graduation and somewhat similar pattern as GATE.  

How to start preparation for ISRO ?
Syllabus for ISRO exam is not mentioned officially, so we will provide the syllabus based on weightage analysis of previous papers that can help you in preparation of ISRO exam.
Most important thing is list out all subjects and start preparing according to weightage of marks in the previous year papers.
Focus on research and understanding topics while preparing the topic instead of memorizing. It will also help you to crack the interview after the written test.

Resources to prepare for ISRO:
More than 90 percent of ISRO questions will be asked from GATE syllabus. So you can depend on GATE syllabus or undergraduate syllabus to cover the topics for ISRO exam.
Once the syllabus is covered, you must practice previous year questions of ISRO. Because 20 to 30 percent of questions would be repeated from previous year.
You can practice the questions from GATE, DRDO, other exams previous year questions. Here GATE exam could cover difficult (time taking) questions and you can omit such questions in your practice. Because ISRO questions will be asked easy type but requires understanding of fundamentals. Many of the questions of ISRO exam depends on facts, formulas and methods/techniques.