Check out Marlowe

 Marlowe is an online "AI" program that looks at and evaluates your work. You can find it here.

I've used the basic version (free) and it does a decent job of checking about overused words, issues with spelling, and things like passive voice and adjective use. 

Most nicely, it gives this to you in a report, which can be put into a variety of formats, ranging from PDF to doc. It's useful, especially at free, and can help you discover if say, those "few" passive phrases you've been using are actually growing like Kudzu. 

Now, there's a reason I put "AI" in quotes. Remember, that Marlowe isn't a real person. It's a program, working from a list of rules. And those rules may or may not fit what you're intending to do. I've found that the more formal your language, the less likely a screaming mistake on the part of the program is. But chatty, informal style writing, especially if you're trying for something that is unusual--yeah, take with a king-sized grain of salt. 

Still, it's pretty useful, and I don't regret signing up to it. I can't say whether or not the paid version is worth it, but I'd say give the free version a look.