Work out the full cost
Add the balance transfer fee to the interest you would pay after the promotion ends on anything still owed. Compare that with staying put.
Set a monthly target
Divide the transferred amount plus the fee by the number of promotional months, and pay at least that each month.
Automate your payments
Being more than 60 days late can end the introductory rate and, on a deferred-interest plan, trigger interest back to the purchase date.
Keep purchases off the card
The CFPB warns that new purchases on a card carrying a transferred balance won't get a grace period.
Note the end date
Put the promotion's end date in your calendar and aim to finish early, especially on a deferred-interest plan.