Today's nitpick involves the possessive, "its."
When you write about something belonging to a woman, you don't say "her's," right? Just "hers."
When you write about something belonging to a man, you don't say "hi's," right? Just "his."
The same goes for things belonging to another thing, no apostrophe. "Its."
As such, "it's" can only mean one thing, "it is."*
This one even trips up professional writers on occasion, so I'm not expecting miracles. But it seems simple enough to me. Just remember how dumb "hi's" looks and you're almost there!
* before someone gets clever with an Addams Family reference, please recall that Cousin Itt's name was spelled with two t's!