How to start prepareing for iit jee in class 10 without join any coaching of iit jee?

Great to see your enthusiasm.

You're in class 10 so concentrate on your board exams first.

DO NOT join any coaching classes now. I would advice you to buy some books. But, first complete your class 10 syllabus. Try completing it by September, 2016. Then start with Class 11 syllabus.

The first book you should buy for IIT preparation is the NCERT. Buy NCERT Physics and Chemistry. For Maths, buy R.D Sharma(CBSE). Start from ground level. Try finishing at least 50% syllabus of class 11 by the month of December. You can get a home tutor for the subjects you feel is difficult for to understand. All this time, do not forget to keep in touch with the class 10 syllabus. From January, start your revision for Boards. PLEASE, do not neglect your boards. It's your first one.

Once you finish with your boards, join the best coaching centre in your area. 2 yr classroom program. By that time, you'll be ahead of most students in your vicinity. So, keep advancing towards completing your class 11 syllabus just like before. You should also keep practising the question banks the coaching centre provides you with. Show your doubts; do not hide it because you think it's stupid.

Your goal should be to be ahead of everyone in syllabus completion: your school and your coaching centre. Do not worry about your class 11 exams. It would be fine, if you study JEE diligently.

I think that's it. You'll be in flow once you join a coaching centre in class 11. Just try follwing what I asked you to during Class 10. That would do the trick.

All the very best for your bright future!!