Have the confidence of self sstudy.
So what ever happens we will study for sure.
So i tell u that : 
    First of all u have to study ur ncert books , then only u shud begin looking at other books .
   And studying means not just reading five or six times , when it comes to IIT JEE preparation , when u are seeing a topic , then it should be learnd completely (100%) , otherwise it will be really difficult to get into the iits.
    Before doing anything, everything, you shud make a timetabe for the whole year or so regarding ur preparation ..and follow it on a regular basis....later on it will be a part of ur life ...and becomes easy...then will begin thinking that  " IIT JEE preparation is one of the easiest and joyful in my life " - believe me!
   Books that u shud consider after the ncert s are :

Maths:
 Trigonometry and coordinate - S L Loney
 Calculus-- I A maron (many topics have to be deleted, bt overall its     a nice one for getting the concepts)
 Algebra- hall nd knight
 and for the rest of topics, arihant and TMH is gud, and for practice too

 Chemistry
 physical-- RCM (bharti bhawan publications), P Bahadur
 organic - morrison-boyd, sanyal and sanyal, I L finar(many thing shave too be  deleted) and for practising the questions, do frm TMH ...it has gud questions...
inorganic,J D Lee is gud, but even just a text-buk , or any refrence buk like ABC will also do
And dnt neglect the NCERT at any cost

Physics
HC Verma ...the book is bible of physics, nd if u study it "religiously", u'll get everything in physics,
NCERT for class 11-12
irodov for practising sums...(but not all)

Thats all  friends
ALL THE BEST FOR UR PREPARATIONS.....STUDY WELL ...