I have this little reminder posted by my computer:
Its is the possessive pronoun; it modifies a noun.
It’s is a contraction of it is or it has.
Incorrect: The mother cat carried it’s kitten in it’s mouth. (possessive pronoun, no apostrophe needed)
Correct: The mother cat carried its kitten in its mouth.
Correct: I think it’s going to rain today. (Contraction of it is)
Correct: It’s been a very long time. (Contraction of it has)
Sometimes I still get its and it’s wrong. I think it’s because of the usage of other words that show possession or ownership. In those cases where adding an ‘s shows ownership, I like to think of that particular word’s apostrophe mark as a little hand scoop – kind of like the ‘s is inviting you, too, into its possession.
As a writer, when I use its or it’s improperly they can be ineffective and unproductive, especially if I fail to show possession by incorrectly using ‘s.
For if you possess these qualities in increasing measure, they will keep you from being ineffective and unproductive in your knowledge of our Lord Jesus Christ. 2 Peter 1:8 Read the beginning of 2 Peter to find out what lack of qualities can make you ineffective and unproductive Christians.