Picking up on what others have touched upon, I must say that I find it tiring, even boring, when I try to read a story that has spelling, grammatical, and especially punctuation errors. I sometimes think that the little country schools that I attended in rural America taught these things better than any school of the last 20-30 years. So many of those stories, no matter their storyline, end up being boring and only partially read by me, simply due to having so many errors.
I'm not expecting completely error-free work from everyone--I'm sure I have some errors that my proofreading didn't catch. Buy a book from a book store on story writing, in general. They would be a big help.