Today I went to mall just to buy clothes and then I remembered this "mission". So I thought, eh what the heck...
I remembered this only when I bought everything and was heading to the exit.
Approach Nr. 1
Ignore

))))
Approach Nr.2
Just outside the mall. I opened a 3set 0.o bla bla bla, we are talking... ...akward silence. Fail. I think I was not liked by one of them or something. She always was staring at me kind of strange angry way. Anyway I told her "Try to smile more, you look better when you do so". Response - "I cannot smile while eating bla bla bla (fuck off basically)"

Anyway I told one of them that she looks very pretty and that I want to get her phone number (she was smiling a lot) and got response - "I won't give you my phone number!". GL HF game over. I went home and I was not angry or crushed, I was happy because that 3set was very funny to me even I fucked it up hard.
Anyway I will try to do more opens and see how they will go. But I still don't understand why I did not got the number tho...