The best way to learn English is by reading and trying to understand what is going on in the text study words and their prefixes to know what they mean. If you understand a few words in a text you will gain a better understanding in what the author is trying to say and develop better English skills
Read books, find out the difficult words and find it's meaning. This will enhance your vocabulary. Watch talk shows and speak English with your friends and family members.
The salutation is to greet the person you are addressing, it goes before the introduction. The introduction is a brief summary of the letter itself and the body is the letter itself.
