I don't think I've posted about this before. A lot of people think passive writing is simply using the word "was".
You can have 'was' in a sentence and it still be active.
A passive sentence is one in which the action happens to the subject, rather than the subject performing the action. However, the word 'was' usually indicates weak writing. So check that manuscript!
A word of caution. I'm reading a HUGE bestseller that's filled with 'was's. I keep mentally rearranging the sentences. So don't go overboard and change everything. Sometimes 'was' is necessary and sometimes it makes the sentence sound better.
The important thing is that your writing zings. Watch out for passives and that will help propel your words to a stronger level.
Here's some links to articles that say it better than me:
http://ezinearticles.com/?Writing-Tip:-Active-vs.-Passive-Verbs&id=301033 (Notice in this article that both sentences contain the word was.)
When did you learn about passive/active voice? Before or after your first finished manuscript?
Me? After. :-)