Yes, you need a comma before "OBE" when it is used as a direct address or a way to call someone's attention. For example, "John, OBE, please come to the front." This comma sets off the title "OBE" from the person's name, making it clear that "OBE" is not part of the name but an honorific.
No. There is no word in English that always requires a comma before it.
It is usually not necessary.
Typically, there is no need for a comma before the word "as." However, using one is not technically wrong, just superfluous.
A comma typically goes before "so" when it is used at the beginning of a sentence to indicate a reason or result. However, when "so" is used as a conjunction in the middle of a sentence, it does not usually need a comma before it.
Before EX: I need eggs, and butter.
The general rule is that it doesn't need a comma before it. Example: I like apples as well as guavas.
not in all cases.
A comma is typically used before "but" when it connects two independent clauses. However, if "but" is joining phrases within a single sentence, a comma is not necessary.
you don't need comma
When which is used to introduce a nonrestrictive adjectivial clause it must it must follow a comma. But there are numerous examples where which does not need to follow a comma. Including: Which melon do you want? I can't tell which melon to buy.
yes
Before. Example: I would have punctuated correctly, but the friendly folks on answers.com were misinformed.