How to start a Letter writing

Dear Sir

I wish to know that if i can start writing a letter by addressing as Dear Sir, and then start the paragraph with 'at the outset............' . I wish to know if it is mandatory to start the paragraph with capital letters especially in the letter format as suggested about.

Kindly let me know on the above.

Regards
A.Nagarajan

You can use Dear Sir, or Dear Sir or Madam,.
Capitalise the first word of the body of the letter even though you've used a comma in the salutation.

Thank you for the reply. It clarifies what i wanted to know
Regards
nags572000

Thank you editor for your prompt response to my query. However my colleague and friend Colonel Rajkumar wants to know whether it customarily in use or grammatically in correct to start with small letters instead of capital letters.

I would always start with a capital letter.