Notice that since I took a direct quote from John Smith's book, I placed those words in quotation marks. Notice also that I placed the date that the book was published directly after the author's name in parentheses--this is proper APA format. Finally, notice that because I explained WHO wrote the book and WHAT book it comes from, the reader is easily able not only to find the source on his/her own to check my facts, but the reader is also more likely to believe what I have to say now that they know that my information comes from a credible source.
When you integrate quotations in this way, you do not use any special punctuation. Instead, you should punctuate the sentence just as you would if all of the words were your own. No punctuation is needed in the sentences above in part because the sentences do not follow the pattern explained under number 1 and 2 above: there is not a complete sentence in front of the quotations, and a word such as "says," "said," or "asks" does not appear directly in front of the quoted words.
If you deploy a lot of quotations in your essay, it appears as though several people are talking about the topic apart from yourself. This would downplay your own voice and leaves little room for your own ideas. It is your essay and it should be your voice that needs to be heard, not some notable/famous person’s. Quote as infrequently as possible. So, don’t cram every quote you know into the essay. As a rule of thumb, refrain from using more than 2 quotes in any essay. (One in the introductory paragraph and the other if necessary in the conclusion)