In letters to members of your family, the salutation should be:

My dear Father / My dear Friend / My Dear Sister etc.

Note that My Dear is more intimate and affectionate than Dear.
In letters to friends, the salutation should be:

Dear Peter / My dear Peter

If you are writing to an older person, you should address him as Dear Mr

Peter or Dear Ms Alice.

In letters to strangers, the salutation should be Dear Sir or Dear Madam.
Avoid phrases like ‘Honored Sir’ and ‘Respected Sir’. Native English speakers don’t use expressions like these.

After the opening salutation, Americans may put a colon or a comma. In British English, a comma is more common.

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There is no apostrophe in yours, either before or after the s.
Write

Yours sincerely (NOT Your’s sincerely)

Before the leave-taking phrase most people write an expression like With kind regards, With every good wish or Hoping to hear from you soon.

Informal letters may finish, for example, Yours, See you or Love. Note that Love is not usually used by one man to another.

Letters which begin Dear Sir or Dear Madam usually finish Yours faithfully. Formal letters which begin with the person’s name usually finish Yours sincerely. In American English, Yours faithfully is not used.