Apostrophe Mistakes In My Writing

Out of the ten writing errors, number eight, which is apostrophe misuse, concerns me the most in my writing. Thinking about all the apostrophe mistakes I have made in my writing, I know that I need to work on it. I find the concept off apostrophe misuse to be difficult because when an “s” is already at the end of a word I feel like I only need to add an apostrophe. Not really watching sometimes if the word is a first name or last name, I put the apostrophe without the “s”. An example is “Charles book” should be “Charles’s book”, but instead I put “Charles’ book”. I have pondered and decided that I do these types of errors because I don’t look deep enough at my writing to find these errors. A second reason for my errors is that I type to fast