I think I've just recently managed to grasp the difference in pronuncation between "o" and "ö" after an "l" (by trying to improve my accent). That's... Well, I've long classified myself as a slow learner... By the way, the sounds are quite distinct in the way the lips are supposed to be shaped. Or, well, I think there might be another hidden distinction - between the short "o" and the long "o" (which is similar to English). But the sound for "ö" calls for a kind of timid smile. I don't know if that makes any sense.