A common way to write poorly is to use “it” as the subject of a sentence when you decide you’d have to think too hard to come up with a real subject. For example, I could have written, “…when you decide it’s too hard…”
This use of “it” is called a false subject (or dummy pronoun in the comic).
You have to work harder, but your sentences will be clearer and have more punch if you avoid that two-letter monstrosity. (I should add that “there is” is just as bad.)
Of course, I have an exception. You may use “it” when you reference the weather. Hence this XKCD comic:
I confess that I sometimes wonder what the domain of that percentage refers to, myself.