Welcome to my series of grammar tips! I love grammar, and it’s kind of amazing how little we native English speakers actually learn about English grammar in school. We learn a bit about it in elementary school, but most of it we just sort of have to figure out through practice. This has led, in my experience, to most native English speakers actually knowing a lot less about grammar than they think they do (including me before I studied it in continuing education). So I’d like to clear some things up!
I’d like to start off with one of the most common mistakes I see and hear in everyday speech and writing: mixing up the subjective (“I”) and objective (“me”) cases of the singular first-person pronoun, especially when the pronoun is combined with another name or pronoun.
I think some of this problem is a hypercorrection that arose from back when we were in school, and someone would say something like, “Me and Jason finished our assignment!” And the teacher would say emphatically, “Jason and I.”

And the teacher was right… in that context… because “Jason and I” was the combined subject of the verb “finished.”
But now, people want to put “Jason and I” in all kinds of places it doesn’t belong, like “Are you coming to the party with Jason and I?” NO. Here, Jason and the first-person pronoun are the object of the preposition “with,” so it should indeed be “Jason and me.” (It could even, grammatically, be “me and Jason”; we just conventionally put the other person’s name first out of politeness.)
If you have trouble figuring out whether the pronoun is the subject or the object, there’s a simple solution. Just take away “Jason and.” You wouldn’t say, “Are you coming to the party with I?” You’d say, “Are you coming to the party with me?” Just like you’d say, “I finished my assignment!” rather than “Me finished my assignment!”
And it’s that simple!