I think it's much too early to buy for travel in May 2014. In the past few years* there have been fare reductions offered in March for travel through mid June; fares have dropped by at least one third for travel at that time.
*Past performance is no indicator of future results, but these reductions have been offered for the last three years, and I certainly hope they'll continue in 2014. The lower fares haven't been marketed as a sale, at least not by BA, they've simply been a matter of lower fares available for those checking the website.
Start looking more closely from the end of January. Choose one or two airlines with which you would like to travel and keep an eye on the websites. Make a dummy booking once or twice a week to see what's available for your dates of travel. Once you decide with whom you'd like to fly, call the airline and ask if a group discount is available.
Join the airline's frequent traveller program (if you're not already a member) and form a household account. Those who wish to travel more often with the airline or any of its alliance members will benefit from Miles or Points given to a dozen tATL travellers.