I am more familiar with North America, but my method should work in Europe as well.
Do a daily search, wait for a good price, then jump on it
Each morning, when you turn on your computer to start your work day, the first thing to do is perform a flight search for ever flight you plan to take in the next 8 months. I save the searches so I can perform them with a single click. Over time, you will get a good idea of what a good deal is, and when the flights are cheap, buy immediately.
In theory, any online flight search tool will work for this. In the US, the most versatile tool in my opinion is Flight Matrix which is run by google, and provides the back end data for all other flight search tools, like travelocity or Kayak.
The benefit of flight matrix is that you can do a "calendar of lowest fares" search, and set the # of days to stay as you wish, perhaps 1-3 depending on whether you must return on the same day, or should stay over night. It can tell you what day is the cheapest.
So just set up 6 to 8 searches, do them everyday, and when a sale starts, buy right away.
There is a caveat: Some airlines (Southwest Airlines, for example) are not in this system and must be search separately.