Aquí tenemos una breve anécdota en London.
This is an anecdote that happened to me in an English class. I used to live in London six years ago and I was in a rush to go to my English class, so as the weather was pretty hot, when I got into my class everybody was sat and my first words that I said to the teacher was, ufff and sorry but I was running and I am sweeting instead on telling that I was sweating. So the teacher explained to me that I had to pronounce like sweat and not like sweet.
So I realized that the way to correct your pronunciation was thorough the people you see every day and they correct to you