How can I take away 20 thousand dollars or more from the price tag?

I will be buying a house very soon and the prices the company I want to go with are giving us very high prices. I need to go down by about 20 thousand dollars. What are some things I don't have to do with the builders so I can save money??? For example: put shelves in the closet, finish the basement, get roughed in air conditioning, etc... I need more ideas