How to study for audit ??

In IPCC auditing, the important topics are SA, company audit,  special audit and vouching/ verification.. 

I followed Vikas Oswal sir's book. I think in Auditing, you can link auditing standards with accounting standards. Company audit with company law. You can also remember many audit procedures with the practical audits you do in your office.

The best way to score marks in auditing is by giving elaborate answers by covering all aspects. Eg. When a question is asked on SA 550 - related parties, you can also write about AS 18 -related party disclosures. You can also touch upon SA 240 related to frauds, and also Section 143(12) of Companies Act so that your answer is complete in all aspects.