Hey,
Thanks for your answers and thanks Eugene-p for that lesson.

It's really difficult for me to make them sound different, even though I can clearly hear the difference. And then, it also seems to depend a lot on which letters are before and after this consonants.

I have just made some recordings, maybe you can see my difficulties. =(

ль
л - ль
лампа - лес

ть
думает - думать
достопримечательность