For me, Maths seemed to be the toughest nut to crack. I always committed silly mistakes in Maths. There are a few books that are very helpful for this.
1.) Calculus : for this, Arihant integral and differential calculus is the best book. It contains enough objective as well as subjective questions that are required for Jee.
2.) Coordinate Geometry : again Arihant coordinate geometry is the best book.
3.) Vectors and 3-D : for this, I used M.L. Agarwal book. This book is the prescribed book for ISC board and is really good for basics.
4.) Trigonometry : any board level book is sufficient for this. Rd Sharma would be a good option.
5.) Algebra : TMH (Tata McGrawHill) is a good option for this.
Maths requires a lot of practice to be a master. You need a really good exposure to a variety of problems rather than just reading the theory portion again and again.
Basal coaching sheets are also helpful. Most important thing in Maths is getting a good exposure to a variety of problems.