I see "it" all the time in manuscripts, including my own, but I never realized how big of an "it" problem I had until I started working with my publishing house to edit The Reinvention of Skylar Hoyt manuscripts and my editors were marking out "it" an embarrassing amount of times.
Now, "it" is often a necessary word. There's one rule about using it that I find particularly funky, which is:
It's = contraction for it is.
Its = Gets used like "Their conversation turns to its usual minutiae"
But if you're using "its" in a possessive way, there's no apostrophe.
So while I know it looks right to say, "The coffee sloshes inside the confines of it's cup." That's not right. You write it, "The coffee sloshes inside the confines of its cup."
Now that we have that out of the way, let's talk about why it gives us such trouble. "It" is not specific. In one sentence "it" refers to a dog, in the next, the sunrise. Whenever you can, use a specific word.
Let's look at an example that I pulled out of a work in progress:
She turns it over in her hands. “You read it, I suppose.”
“I did. I shouldn’t have when I realized it wasn’t for me, but I did.”
“It doesn’t matter.” She tucks it into her bag and sets her shoulders.
5 uses of the word "it." You can likely tell the girls are talking about a note - especially within context - but I'm really making my life harder on my reader. I'll leave it in the dialogue, but the others I'll try to get rid of. Maybe, "She turns the note over in her hands" and "She tucks the square of paper into her bag and sets her shoulders."
There's a balance with this of course. Like in these lines:
...I say, tipping my head back to enjoy the last drop of Coke. It’s a sympathy can. Ella and Katelyn bought it for me as a consolation to losing Dave.
It would be cumbersome to replace the "its" in here.
...I say, tipping my head back to enjoy the last drop of Coke. The Coke is a sympathy can. Ella and Katelyn bought the Coke for me as a consolation to losing Dave.
Makes me giggle, which isn't the response I'm trying evoke from my reader.
One last thing is you should get in the habit of double checking sentences that start with "It," especially if it's the beginning of a paragraph.
Like if you're starting off a paragraph (or a scene or a chapter) with "It was cold and rainy, and I didn't feel like doing anything." You can pull your reader into the scene better if you replace "it." What was cold and rainy? The morning? The afternoon? The first day of school? The day her parents told her they were getting divorced? "The afternoon was cold and rainy" at least tells the reader something.
Evaluating your use of "it" in your manuscripts is a great way to tighten up your writing and add description. I can think of lots of cheesy closing lines involving the word "it" but I'm going to suppress my dorkiness and refrain.