The Amex transfer bonus I've waited a year for is back: Get 30% more Avios

Transfer bonuses are one of the best ways to get outsize value from your credit card points and miles. In fact, they're often how the people you see frequently posting photos from lie-flat business-class seats booked those flights ... without having millions of points and miles at their disposal.But they're notoriously hard to predict, which can make using them tricky if you have a set timeline for booking your next trip.One transfer bonus, in particular, hasn't been available for the past year, much to my disappointment. Fortunately, it's now finally back.From now through Sept. 27, you can get a 30% bonus when you transfer your American Express Membership Rewards points from cards like the American Express® Gold Card and the American Express Platinum Card® to British Airways Club, Iberia Club or Aer Lingus AerClub.During this bonus, you can once again book flights from the East Coast to Dublin in business class for 39,000 transferred Amex points (plus $144 in taxes and fees) and ones from the West Coast to Hawaii for 17,000 transferred Amex points (plus $5.60 in taxes and fees) via British Airways, among other options.Here are six tips for making the most of this relatively rare t...