And because I know it's what you've been dying to read all day, I've compiled a short list of words that people ALWAYS mix up. Wait—words? Isn't that about spelling? NO! It's all grammar. When you write the wrong word, it skews the meaning. Grammar is all about making writing clearer. You can be creative until the cows come home, but it's not going to do much good if no one can understand what you mean.
1. Your vs. You're
Your = Your hair is on fire.
You're = You're really stupid.
Your is an adjective.
You're means "you are."
2. There, Their, and They're
There = I left my book over there.
Their = My mom wanted to borrow their recipe.
They're = I think they're coming later.
There means location.
Their means ownership or possession.
They're means "they are."
3. Effect vs. Affect
Effect = The weather has a negative effect on my condition.
Affect = The weather affected me negatively.
Effect is a noun 99% of the time.
Affect is always a verb.
Now, if you even read that, it's likely that you'll forget it. I'm feeling a little pessimistic today. Sigh. Oh, well, I guess I have nothing to say since I remember next to nothing from pre-calculus class my junior year of high school. "How is that applicable?" you ask. IT'S APPLICABLE! Because I love grammar, I remember it well. As for math, all I remember is that 5 + 5 = 11.
But hey. We can't be good at everything, can we?