Usually we use simple questions.
- What’s the time.
- Nice shoes/t Shirt/book/glasses/mobile
- Asking the way out
After initial interaction you ask subservient question as follow up which continue the conversation.Always keep questions short and open ended i.e. requiring a view and not a yes/No response.
Take your hints. If you still connect and they respond positively then go ahead.
PS : You need to practice a lot.The success rate for very conversant people is also less than 10%. Don’t be disheartened by your efforts.You can learn only by practicing.