Capitalise the first word of the text (even if the salutation ends with a comma). The text is left-justified and a blank line is put after each paragraph. It is not common to indent the first line of a paragraph.
- first paragraph: introduction and reason for writing
- following paragraphs: explain your reasons for writing in more detail, provide background information etc.
- last paragraph: summarise your reason for writing again and make clear what you want the recipient to do
Note: Your text should be positive and well structured.