Focus mainly on the most important topics. Learn all the important formulas. Makes notes of all the important stuff.
Discuss the difficult topics with coach/teacher . If possible try some online mock test as well.
Wish you the best.
I suggest you contact some of your friends and known circle peoples to get the study material.
Also, you may find this site useful.
IIT JAM Exam will be conducted in the month of February. Start your preparation for the JAM Exam now.
Best of Luck!