How to use a quote within a quote

Using a quote within a quote is not a difficult thing at all. We just need to get the logic right and then the punctuation become really simple.

We must use single quotation marks for the quotes within the main quotes. Now the period mark / question mark should always be inside the most interior quote marks.

Example of using a quote within a quote:
She said, "Maria exclaimed, 'Oh my God!'"
If a question is to be quoted, the question mark should be placed inside the quotation marks. 
Julie said, "My husband asked, 'Where can we go for dinner tonight?'"