The passive is one of those things authors seem to either love or hate, and then there's the advice not to use it in your writing. It's considered to make your writing dull and boring, and you should avoid it at all costs. If you don't, your writing must be horrendous. I don't think this is true, and I'm going to tell you why. If the passive had no purpose, why then is it part of the English language?
Let me start by saying this particular piece of advice has been pulled out of proportions in many ways. It isn't exactly a 'don't use it at all' but rather a 'use it sparingly and wisely'. To understand when you should or shouldn't use the passive, it's important to know what it's used for, and the name already implies it.
Something is passive, but what?
We have two types of sentences: the active sentence and the passive sentence. In writing, it's the active ones you will use the most. In an active sentence, the emphasis is on the subject doing something, i.e. 'I am writing a blog post on the passive.' By writing it this way, I want to convey the message I am doing the writing, not someone else.
In a passive sentence, the emphasis is on the subject undergoing something; something is happening to it. They're not actively doing something. 'A blog post on the passive is being written by me.' In this case, I want to emphasise the blog post on the passive; that's where I want to draw the focus to. It's not important who is doing it, just that it's being done.
In your writing, that is what you want to look out for when dealing with the passive. Ask yourself what you want to put the focus on. Obviously, in a fighting scene, you want your tenses to be active; you want to show what is happening at that time. You want to keep a fast pace (because the passive can take away from your pacing, which is why it should be used moderately).
But what if your character has been kidnapped, for example? They are blindfolded, gagged, and tied up. They cannot do anything, and they miss two of their senses. This is when you might consider using the passive, to put emphasis on what is being done to them rather than what they are doing or what their captors are doing.
My hands and feet were tied, a gag had been stuffed in my mouth, and I had been blindfolded by a cloth which smelled vaguely of shoeshine. Something shuffled closeby, a rat perhaps, but other than that, the room was quiet. I couldn't remember much of what had happened. My last real memory was of being pulled into a van and then...nothing.
In this example, the passive is in bold, but as you can see, I want to put emphasis on the things that were done to this character rather than what their captors were doing or had done. It's a choice. You could write this actively, but you'd be focusing on the people who were doing this rather than the main character. Is either wrong? No.
Another example would be when you are describing a place, let's say a room. Is it important what that room is doing or would you rather put the emphasis on what it's undergoing (being observed by someone who came in for the first time?).
The room wasn't anything grand and reminded me of 1001 Arabian Nights rather than anything else. Curtains in various colours and fabrics were draped along the walls; lanterns in all shapes and sizes had been placed throughout the room without rhyme or reason. Rugs in of various patterns were covering the floor, and cushions had been laid in a haphazard way/
In this example, I want to put emphasis on the 'objects' and what had been done to them and not on the person who did it. Perpaps the room has looked like this for a long time, so the point of who did it is moot. Again, it's a choice. You could write this in active sentences as well, but it changes the focus.
Please note. Some advice I have seen going around about the passive is that when you see a was or were, you're dealing with the passive, so you should change it. This is not the case. Was and were are modal verbs of the past continuous and are considered active (was sitting, were writing). Do me a favour, and don't blindly take out your wases and weres. They're perfectly okay to use.
How then do you recognise the passive?
One of the most well-known ways to do so, is to check if you can add 'by zombies'. If the sentence still makes sense, you are dealing with the passive.
'My children are eating icecream.' --> Active
'Icecream is being eaten by zombies.' --> Passive
To be fair though, for this to work, you have to understand how the passive is formed and what to look out for. Like active sentences, passive sentences use the tenses, except they must always have a form of 'to be' + past participle.
I write a book. = A book is written (by me).
I am writing a book. = A book is being written (by me).
I wrote a book. = A book was written (by me).
I was writing a book. = A book was being written (by me).
I have written a book. = A book has been written (by me).
I have been writing a book. = A book has been being written (by me).*
I had written a book. = A book had been written (by me).
I had been writing a book. = A book had been being written (by me).*
*These forms exist, but I doubt they're used very much.
So, the passive has a purpose, and it's all about the emphasis. You just need to consider what is important. Especially if you use editing software, you want to be careful changing it. Your editor may not agree with me; the passive is a tricky thing, but I firmly believe it can and should be used, or the English language didn't still use it. You just have to do so wisely.