Thanks for your advice loved it and also want to ask one thing what would you recommend for maths cause it a bit weak from my side  

As far as maths is concerned as per the BITSAT point of view , they don't ask much long questions , the questions are usually easy to moderate and as I have told just go through the formulaes very well because they also ask formulae beased questions and for example in calculus , they ask the special forms of integration or differentiation , so just keep in all this.Sometimes you can predict the ans in maths from the options directly by eliminating the wrong ones.
Hopes it helps