The key to a lot of mix-ups like these is that these words all fall into categories that include lots of other words formed exactly the same way. So you can remember the right word by thinking about the other words in the same group.
Just sharing with you what helped me:
its
is possessive
The word is patterned like a possessive:
yours, his, hers, its
The state government in Albany has lost its credibility.
it’s
= it is
The word is patterned like other contractions:
I’m, you’re, he’s, she’s, it’s
It’s time to think about taxing goat cheese, before it’s too late.
your
is possessive
The word is patterned like a possessive:
her, their, your
Your tarantula just died.
you’re
= you are
The word is patterned like other contractions:
I’m, he’s, they’re, you’re
You’re not going to believe who won a Grammy.
their
is possessive
The word is patterned like a possessive:
our, your, their
I like the Martians, but, boy, their spaceships sure are ugly.
they’re
= they are
The word is patterned like other contractions:
we’re, you’re, they’re
The Ravenclaws aren’t coming. They’re going to Fred’s party instead!
there
is a location
The word is patterned like other pointing terms:
here, there, everywhere
I’ve always wanted to visit the planet Skaro, but I’ve never actually been there.