Not even aimed at anyone in particular, just anyone guilty of these. Please, please, please. Please. It's so simple.
Your = possessive adjective, and more specifically, the possessive form of the word you. "They want to pet YOUR dog." If you use "your", you have to be able to answer the question "your what?" with the next word.
You're = a contraction of "you" and "are". That's it - it's short for "you are". It is only to be used in a sentence where you could replace it with "you are". What could be simpler?
To = shows direction or directs a sentiment. "We are going TO town." OR "Happy birthday TO you." That's it.
Too = shows excess, or replaces "also". "I added TOO much salt." OR "Can I have some, TOO?" As a way of remembering...if you want to show excess or replace "also", just use "too many" o's (as in 2, instead of 1). Get it?
There are also the other forms, "yore" (as in "days of yore"), and "two", as in the number, but if you're misusing those, I don't know what to tell you. Stop writing until you retake English class.
This is basic stuff, folks, and while everyone is guilty of the occasional misuse (it would only be as a typo in my case - my english teachers taught this unceasingly), we should all know the difference by now, shouldn't we? Really? Please? I'm begging you. Thanks.