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.
I started in London, as a kid. My mother knew I had sort of an inbred talent. She was an actress, so I inherited it from her. But I think I got a lot of it from my grandfather, who was a great politician.