(1) Its and It is
A common mistake and one that drives teachers of all levels crazy, is the mix-up between the words "its' and "it's". "its" is a possessive pronoun, meaning 'belonging to it'. The confusion arises because if you don't substitute the pronoun "it" for the noun, an apostrophe is used. For example. the bone belonging to the dog is "the dog's bone.". The eraser on the pencil is "the pencil's eraser." Both examples use an apostrophe plus an "s" in order to attribute ownership. However, when a noun is changed to a pronoun, an apostrophe is no longer used. Instead of "a rabbit's cage" you might say "its cage". Instead of "the house's window" you would say "its window." This tends to confuse people who are used to apostrophes denoting possessives.

Other examples of the possessive "its" could include the dog burying its bone in its backyard and the table which has its leg broken off and its table cloth in need of ironing. "its" is a contraction. A contraction is when a new word is formed from two or more separate words. In English, an apostrophe is used to acknowledge the missing letters. "Don't" is a contraction of "do not" and "shouldn't" is a contraction of 'should not'. In the same way "Its" is a short for 'it is', or less frequently for "it has". Any time "its" includes an apostrophe, the writer should be able to substitute "It is" or 'it has" and have the sentence still make sense. "It's going to be my birthday tomorrow" is correct because it can be changed to "It is going to be my birthday tomorrow. "It's been two hours since I have eaten," can be verified since changing it to "It has been two hours since I have eaten" is still correct. Therefore, it's easy to get the two words mixed up, because English does not always follow its own rules.

(2) Anyone vs any one
"Anyone" means "any person," not necessarily a specific person. It could refer to multiple people simultaneously. As two words, "any one" refers to a single person.
Example: "Anyone can download my software. But a single-user software license can only be used by any one user at a time."

(3) Do the quotes go after or before the full stop?
Put quotation marks after a full stop or comma.
Put quotes before a colon.
Put quotes after a question mark unless the entire sentence is a question.
Example: He asked, "Are you Hungry?"
She replied, "yes." Did she say, "yes"?