This is more of an informal question. I am studying microeconomics theory and have completed the intermediate microeconomics by Hal R.Varian. I really enjoyed the book and want to upgrade my skills. So please suggest me some good books that would serve the purpose. Thanks.
If you would like to go step above Varian's intermediate microeconomics and you like Varian as an author then his book Microeconomic Analysis is on graduate level.
However, I personally prefer more Mas-Colell, Whinston, and Green (MWG) Microeconomic theory. That is probably the most comprehensive microeconomics textbook there is on the market.