To qualify the IIT JAM is not an easy task. To qualify it you have to be dedicated and passionate about your aim.

The first step to start preparation for any exam is analyze the complete syllabus. Then go for the paper pattern through which you will get an idea about the marking scheme and duration of the exam.

By doing these you will easily make a well-planned strategy for preparation. Time management is necessary to follow this preparation strategy.

Revision is must, to remember everything which you have studied. So, do revision after completing each topic.

Always be positive, be hopeful and be confident.

All the Best!!

You can refer below study material for your preparation

O.P. Agarwal

J.D Lee

R.A. Day Jr. and A.L. Underwood

R.T. Morrison and R. N. Boyd

R.A. Day Jr. and A.L. Underwood

H.J Arnikar

CNR Rao

A.G. Sharpe and Catherine E Housecroft

You should also solve previous year papers to know the exam pattern and to know the level of the questions. 

Solve complete mock test as well for your practice.

Good Luck!!