everything多用于肯定
而anything多用于否定和疑问语气
anything
1) 任何事情/东西， 可以用在肯定句/否定句/疑问句中。
如:You can take anything you like. Do you have anything to say?
There is not anything you like here.
2)意思为“something” 的疑问/否定形式。
如：--Is there anything in the box？ --No nothing.
He has not anything to do today.
everything 所有的事情／东西，如：Everything here is all right.
另外：not anything =nothing ; 而 not everything 并非／不是所有的东西／事情
楼主有具体问题可以追问
追问is everything ready?
is anything ready ?哪个对
anything here is cheap.
everything here is cheap. what are the differences
追答口语的话就随意了吧....
但是如果是答题，保守点的话问句选anything，陈述选everything比较合适吧
参考资料：百度百科