When you are writing an MLA style paper it is important that your paper is:
Citations are a way for you to cite the sources that you used in such a way that anyway who reads your paper is able to find the source in your works cited page and view the source themselves.
If you are inserting a block of quotes that are more than three lines. Larger blocks of quotes should be limited especially if your paper is small in size. If you have multiple large blocks of text it can seem as though you are trying to fill the page lengths. You can often do with a shorter quote in these cases. But if you have a good reason for including a longer quote make sure you indent the quote after which you need a parenthetical citation to follow the period at the end of the sentence. Do not place a comma in between the last name of the author and the page number.
With regard to your citations it is best to skip wordy introductions. You do not need to include any filler when you refer to a source. If the reader has questions about what the publication does or why it is important they can always read it themselves.
While writing you may have a passage that you want to quote which is shorter than three lines. In this instance you can use the inline style of citations. You can break up a quote and follow it with the parenthetical citation. The citation should be listed outside of the quote though. The period for the sentence should be placed after the end of the parenthesis. If for any reason you change the first word in the quote (such as with “…” or a lower case rather than an upper case) you can put  around it.
When you paraphrase an idea it can make it easier for your reader to understand it. But in using this you still need to refer to the content with a passing parenthetical reference. Using another author’s ideas still required citations.
And for each essay you produce you will need to complete a full works cited page at the end wherein all of the sources you used are listed in alphabetical order.