Passive Voice

    I've been struggling lately with PASSIVE VOICE. I get the concept, but not enough for me to be able to point it out in my own writing. I've read that passive voice can be the death of any author because agents and publishers think it's lazy writing and are therefore trained to notice it. Passive voice=query into the bin. But I'm just not getting it. Can anyone give me a passive voice tutorial? Anyone?      What I do know is that the word "was" is a big indicator that you're using passive voice. Like, instead of saying, "It was cold" you should say something like, "the cold seeped into my bones and I shivered". Passive voice doesn't relate to the character, where as active voice does. The thing is, when I'm trying to trim and trim and trim some more, I don't want to get all wordy all the time. Sometimes I think it's better to get straight to the point by saying, "Lord Alric was just as charming as I imagined him to be" (straight out of my book), rather than something a 16-yr-old would never say like, "I had imagined the extent of Lord Alric's charms, and they didn't disappoint".
     I'm wondering if maybe the use of WAS doesn't necessarily make it passive voice. Or, if it's ok to use the was sometimes. When I read about how bad Passive voice is, I decided to look through the first paragraphs of three bestsellers. I counted at least 8 was's in each one. Just in their first paragraphs! So now I'm thinking that I really don't get it. Or maybe it's not so bad as websites and blogs are leading me to believe. Or maybe it is but some people just get away with it. Or maybe- and this is probably the right maybe- passive voice is one of those things that you need to watch out for just so agents/publishers don't have an excuse to toss your MS right off the bat. They see so many on a daily basis that I really shouldn't be giving them any kind of reason not to read past line one.
     Which is why I need a passive voice tutorial. I'm starting to see the benefit of all those writers who have MFA's. I'll just have to stick with my one year at university and one college writing class. Crap.