Hello Kirti,
As regards IDT, refer Bangar because it covers almost everything and follow this sequence:
VAT, Service Tax, Excise and finally custom.
I have mentioned to do VAT and Service Tax first because they are simple topics and fetch 40 marks.
Also dont forget to do case laws from the case study book applicable for May 13 attempt.
And for AMA if you have joined some classes then refer those notes and also Institute's Practice Manual.Its really helpful!