There are many differences between American and British English as regards to spelling in general, but differences in punctuation are minimal.
Actually, there isn’t an official book of rules in America about spelling: the American style was established for typographical reasons, a historical legacy from the use of the handset printing press. It is used by most American newspapers, publishing houses and style guides in the United States and Canada (including the Modern Language Association's MLA Style Manual, The Associated Press Stylebook and Briefing on Media Law (in short: AP Stylebook; http://www.apstylebook.com)etc., which make proposals in spelling questions.
Full stops/Periods in abbreviations: Americans tend to write Mr., Mrs., St., Dr.; the British will most often write Mr, Mrs, St, Dr, following the rule that a full stop/period is used only when the last letter of the abbreviation is not the last letter of the complete word.
Quoting: Americans begin their quotations with double quotation marks (") and use single quotation marks (') for quotations within quotations. In journals and newspapers, quotation mark double/single use depends on the individual publication's house style.
Quotation usage: Americans occasionally place commas and periods inside quotation marks. In both styles, question marks and exclamation marks are placed inside the quotation marks if they belong to the quotation and outside otherwise.
Parentheses/brackets: In British English, "( )" marks are generally referred to as brackets, whereas "[ ]" are called square brackets and "{ }" are called curly brackets. In American English "( )" marks are parentheses (singular parenthesis), "[ ]" are called brackets, and "{ }" can often be called curly braces. In both countries, standard usage is to place punctuation outside the parenthesis.
American English use the comma before the last piece of enumeration too. The comma is