Find the three numbers on your statement
Locate the total amount due, the minimum amount due and the payment due date.
Pay the total amount due if you can
Paying the entire outstanding by the due date keeps you within the interest-free period.
If you can't, pay well above the minimum
Paying only the minimum keeps the account from being treated as overdue but interest still runs on the rest, and new purchases can lose their interest-free period.
Check how interest was worked out
RBI requires statements to show how the outstanding amount used for interest was arrived at. Query anything that doesn't match your payments and refunds.