I'm not sure what airline you are flying, although I will assume it's BA (could also be QF or Singapore - that would be fun; a choice of 777s/340s on SIN-PER).
Anyway, as Luftaom pointed out, the most likely route is across Central Europe, over Germany, Austria, Romania, Turkey, Iran, India, across the Bay of Bengal, down the Straits of Malacca and its first left after K.L.; you can't miss it. Show the crew the map in the inflight mag if they're having a problem!!
Alternatively, you can fly over Northern Europe - Berlin, Warsaw, into Russia, south of Moscow, turning down towards a place called Aktyubinsk, then towards India, rejoining the route from there to Singapore.
Stay awake over India, as there's sometimes some fairly spectacular t/storms and the clouds can just light up every few seconds. I flew QF on this route in '93.