Contractions sound like people talk. So don't be afraid to use them when writing for the ear. I've is a contraction for I have. It's is a contraction for it is. We'll is a contraction for we will.
Active verbs are better for listeners.
They are clearer, more direct, and easier to understand. The boy was hit by the car. So it would be much easier for a listener to understand if you just said it more directly. Like the sentence to the right. It's short and direct.