Hanuman, I'm sorry to say that your question is too broad to handle in a forum post. My dictionary shows 12 definitions of "above" and 34 for "over"! If we limit our discussion to just the prepositional uses where "above" or "over" are spatial concepts, the two are extremely similar.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.