Quotation Marks (" ") --- Used around the exact words of a speaker.

Example One: "Have you been to the new mall?" asked Todd.
Example Two:  Todd asked, "Have you been to the new mall?"

Warning! Do not be fooled by a sentence such as the example shown below. It  is not a direct quote and does not require quotation marks.

Example: Todd asked if I had been to the new mall.

Semicolon (;) --- Used between the clauses of a compound sentence that are not joined by and, or, but, or  nor. It can be regarded as a weak period. Example: I reserved the room for the party; Sally took care of the music.

Apostrophe (') --- Used in place of the omitted letters of a contraction. Example: doesn't = does not --- Used to form possessive nouns. Examples: baby's rattle, student's books, dog's collar

Period (.) --- Used at the end of a statement, request, or indirect question. Examples: I ate the pizza. Speak more slowly. I wonder who will win. --- Used in abbreviations for titles, degrees, and expressions of time.

Sue Clark, M.D.
The play begins at 7:30 p.m.

  Colon (:) --- Used to show a list of items that follows it.
He  participates in three sports: football, basketball, and track.

Do not use a colon directly following a form of the verb be or a preposition.
His four favorite writers are Bradbury, King, Donne, and Thoreau.

Comma (,)

1)  Used to set off elements that interrupt a sentence.
That boy, in fact, worked very hard this summer.

2)  Used to separate items in a list.
  I like hotdogs, cake, and tacos.

3)  Used to set off nonessential clauses and nonessential participial phrases.
Texas, which has the most farms in this country, produces one fourth of our oil.

4)  Used after an introductory dependent clause.  
If you study, you will pass.

5)  Used to set off a appositive.
William Shakespeare, a famous English playwright, wrote  Romeo and Juliet.

Warning! Because there are so many comma rules, people tend to overuse the comma. When in serious doubt, leave the comma out; it's better to have too few than too many.