I can give you the King's English and then I can take it to the street, but do both or do one and don't do one knowing only the street. That's going to hold you back because what comes out is going to impress people, and it will impress them negatively.
At 11, I passed the scholarship - only just; I wasn't very good at maths - to Ilford County High for Girls. When the Second World War started we were evacuated, first of all to Ipswich, and then to Aberdare, Queen of the Valleys, in south Wales.
You do have to do business with and to try to influence people you don't agree with, or find disagreeable, so it's important to stress that balance.