No spaces before commas or apostrophes. I have been teaching English to foreign students for nearly five years now. I have noticed a recurring problem with many of my student's writings. It seems to be habitual for them to type a space before commas. This is grammatically incorrect. In any sentence, like this one, that has commas, there should be no space before the comma. When writing contractions, the same rule applies. There are no spaces before the apostrophe. It's not correct to write a contraction like this: it 's. In fact, in most cases, there are no spaces before any punctuation mark. An exception to that rule would be "quotation marks".