Social skills are everyday expressions and interactions that we might not think twice about, however there are people who need reminders on what is appropriate/inappropriate at different times.
Here is a video from Natasha Daniels, a child therapist, who offers some advice on how to help children of any age develop better social skills.
Everyday Speech is a site that we in the district use very often with students in secondary education. The videos they create are incredibly helpful and cover a large variety of topics. You can also find the videos on www.youtube.com/channel/UCXEWDMFYH8EUa3zv55gXQeg