The basic preparation for all the Management entrance exams, such as CAT, XAT, remains the same. Where you have to focus more is on the Current Affairs section. You can prepare current affairs by reading newspapers, magazines like Manorama Yearbook, GK Today, etc.
Today several online courses also started like CareerAnna, Ravi Handa, which you can join for the MBA exam. Brush up your general knowledge, which might help you to solve some questions along with keeping up with all the current affairs.
The most important thing required to crack the IIFT exam is speed. Therefore, practice and solve the previous 10 years of papers in a limited time to increase your speed during the exams.