edit this for 10 points?

I think it looks fine.

He does not realize that he was so egotistic that he always looked down ON other people. As a result, he has to RELIVE Groundhog Day, which he hates very much, as a punishment and suffer from his own mistakes. For example, he steps in the same pUddle (?) every time when he rudely rejects the insurance offers of his old high school friend, Ned Ryerson. Every day when he sees him, he says, “Can you leave me alone?” or even pushes him off the sidewalk. His manner causes him to go through the same routine of being bugged and annoyed by Ned every day when he walks pasT the street (what street? Do you mean "down the street"?). Also, the immoral way he treats Rita causes him to get rejected and slapped across the face many times. Getting information about Rita as he repeats the day, he pretends to have all the characteristics that her perfect man should POSSESS. He tries to favour (This is too vague. It just means treating her better than others do.) Rita, so she would go to bed with him, which of course, fails IN the end. However, things start to change after the night when Rita tells him, “If tomorrow were the last day, I would help others to make a better world.” He finally realizes his own mistake--that he was being careless with other people and did not treat others with respect. As a result, he starts contributing to society: saving a boy from a tree, helpING old women to fix flat tires, tryING to save a homeless old man from dying, and more. After realizing his own mistake and changING himself to a positive figure, everything goes back to normal and that is how he learns his lesson.

A general comment: You have to make up your mind whether to use the present tense or past tense and stick to it. I have not changed the tenses. I have capitalized some places to make my changes more obvious, but could not do that everywhere, and you should notice where I changed the punctuation, as well.