For travel LHR==>BKK in Dec 2009, I made my bookings with EVA in early September, with Premium economy on the outbound leg for what's basically an Economy price (~£550).

 

This year, I watched prices from August until booking in late September. Prices were maybe £150 higher (some due to taxation). If the fare history charts are reliable, I would have had to book in July to get anywhere near last years price on a direct flight. There were no premium economy offers.

Also, by the time I booked, the preferred return Eva flight on 3 Jan was already sold out (with both EVA and the travel agents). So I booked economy at £704, returning a couple of days earlier.

Now about 1 month later, return Premium Economy flights are available on my compromise date for £717

 

I don't know if sharing experiences here will help us all to get good deals, but shall we start?

Usually I use booking in 3 months in advance and have price from Europe to BKK about $560-610 with Emirates or Qatar Airways in low season and about $590-690 in high season. Past year I got $660 even in Christmas time with Swiss.

 

Sometimes when I have free time I use "last minute" offers for short visits (7-12 days) if have nice offers from charter's market - it can be as low as $380 (all mentioned prices are for 2-way tickets in economy class).

 

I just check - lowest price for now for December LHR-BKK-LHR offer Air India for $770(2-way) Dec.9 - Dec.26 via Mumbai (transfers 1.5 hours)