What's the difference between "dream about" and "dream of"?

Are the any differences between "not good" and "no good"?

learning english I'm been studying english for about four months. I like a lot talking with native speakers on skype or writing with them on Italki. I'm loonking for differents way to learn. For example I use to watch movies (comedy, action movies and other easy cathegorizes) or videos on line. I read English newspapers and books. I use to underline the word I don't know or I don't remember to add my personal vocabulary.