In what kind of scenarios are honorifics such as 大姐, 大哥, and 师傅 used, and when is it acceptable or polite to use them?
For males or females who are older than yourself are not blood relatives e.g. not 表哥 or 表姐 and are usually unmarried and not quite old enough to be referred to as 阿姨 or 叔叔 then this is someone you might refer to as 大姐 or 大哥.

This is normally out of respect to someone who maybe treats you as a younger brother or sister.

In certain movies 大哥 is used for a leader of a gang of street kids or thugs.

This is also normally used for someone younger to someone older, so you won't see many people 40+ referring to someone else as 大姐 or 大哥 unless they have been doing this for a long time.

师傅 is commonly used for someone with skills in a certain area. I have seen this used for a personal carer, a repair man and also someone that teaches martial arts.

Don't call someone without specific skill 师傅, e.g. someone that helped you do something like give directions otherwise they may think you are having a lend of them.