Skyscanner show a bar graph giving the cheapest months to fly on a particular route rather than the cheapest dates to buy the tickets.
Flash deals can be a good option, the airline we can't mention here is having a 3 day sale with some good reductions at the moment.
My usual long haul trip of Singapore - London return has over twenty possible airlines offering one stop or direct flights. Fares tend to be very competitive and there is always someone having a sale on. Even the non stop premium charge over a connecting flight isn't that high as options for easy transits enroute are plentiful and the airlines can't get away with too much price loading as a connection only adds a couple of hours to the trip and there are numerous stop over offers.
As I have my leave requests for the next twelve months done early on in the year, I can choose the cheaper dates, and wait for a flash sale or jump in around the ten to twelve week mark if nothing's been offered.