Iva's answer is excellent, but be aware that "still" has multiple definitions. I'm still at the sea. (I am near the beach, generally a response to a question like "Where are you?") The sea is still. (this is a reference to the sea, stating that the water is very calm)

This is a tricky one :-) Some broad guidelines: Yet: usually used in negative sentences or questions - carrying the idea of an ongoing or pending action which is not yet completed: Have you finished cleaning yet? (I think you are cleaning, and you are STILL doing it, now) I haven't done my homework yet. (My homework is a pending task, I may or may not have started it but it is definitely NOT completed.) Still is usually used in affirmative sentences: I am still waiting to see the doctor. (the waiting is continuing now). I am still unhappy (I remain in the state of being unhappy, it's continuing now)

still means you are doing something continuously. yet means you don't do something even though you need to do that.

Hello Italkian friend, how have you been? We use yet most commonly in questions and negatives, to talk about things which are expected but which have not happened: Is it seven o’clock yet? (The speaker thinks that probably it’s almost seven o’clock.) A: Where will you be staying? B: I haven’t decided yet, but somewhere in the city center We use still not yet or already to refer to the continuation of a situation: I still meet my friends from my schooldays now and then. (I continue to meet my friends) I do hope that will do. Cheers