Hi everyone! ^w^ So, it always gets on my nerves when people use words incorrectly, so I'm going to try to help people use words correctly with this blog xD
Sooo, yeah. Here we go!

Where: a denotation of place. "Where are we going today?"
We're: a past indictative of 'be.' "We're going to the movies."

Witch: something you'd dress up for on Halloween.
Which: asking information about plural nouns/pronouns. "Which dog are you buying?"
Sandwich: a food.

There: shows a place. "I want the box over there."
Their: shows possession. "That's their box."
They're: an abbreviation of they are. "They're going to buy a box."

Your: shows possession. "This is your remote."
You're: an abbreviation of you are. "You're going to buy a remote."

Now it comes time for 'An' versus 'A'

'A' goes before a word with a consonant letter starting it, such as "a horse" or "a box."
'An' goes before a word that starts with a vowel, such as "an apple" or "an umbrella"
But if you want to be a little rebel, you can also say "an hour" or "An honorable person" because the 'h' is silent.

I hoped this little guide helps you with your useage of the English language! ^w^