This article provides a simple way to choose between you and I and you and me.
Consider the following sentence: You and I should have lunch.
Is the correct form of this sentence You and I ... or You and me ...? This is a common source of confusion in English.
Fortunately, there's an easy way to decide whether to use I or me in such sentences. All you have to do is drop the word you then try the sentence with I and me one at a time. For example:
I should have lunch.
Me should have lunch.
Clearly the preferred form in this case is I; thus, the original sentence was correct to use you and I.
Here's another example: He'll blame you and I. Drop the word you then try the sentence with I and me one at a time, like so:
He'll blame I.
He'll blame me.
You can see that the second of these is correct. This means that the original sentence should have been: He'll blame you and me.
On a related note, when using phrases such as you and me, you and I or them and us, it has traditionally been considered courteous to place the reference to yourself last. For example, we prefer:
He'll ask you and me later.
He'll ask me and you later.