Let me start out by saying that it's important to weed out words like "was," "had" and ly adverbs in your manuscript. But just do a word search in your manuscript and you'll quickly find that the task isn't as simple as it may seem. There are two different instances in which we find "was" and "had," one of which is easy to fix, the other, not so much.
the first is like we've mentioned before:
"He was singing in the choir until September of last year." becomes, "He sang"
Easy right? Well, what about that other instance where you can't simply conjugate the word? Well, that is where we all learn to become better writers...
"The sky was grey and overcast."
Hmm... can't just conjugate that one. But let's think about this sentence for a moment. It's just fine grammatically, but for a work of fiction, it's just not very descriptive. It's shallow. So let's dig in a little deep and watch that "was" disappear.
"Alisa looked up into the clouds and noted the way they sagged with the weight of rain. The blue sky all but disappeared as the clouds moved into place, preparing to drench the parched ground."
Well! How about that? We just took a simple sentence and created something beautiful and descriptive with feeling! Our characters only comment on things that are of some importance to them, or effect them in some way. FEELING and description is a crucial part of setting the scene. So don't be so scared of rewriting. It takes work... but your story will come alive.
WAS, HAD and LY ADVERBS are crippling to your descriptions! They cut the picture off at short, sweet and simple. We don't want that! So delve in a little deeper and give your reader a better picture.