My favorite scheduler always recommends to write the narratives in Word for grammar and spelling checks. The advice given so far for facts and an objective voice are spot on. Proofread your narratives before you submit.
Another scheduler said to write reports like an outline for a report that you were required in school. That was great advice to help me organize my narratives. Logical, I know, but sometimes I need a kick in the head.
If your phone can handle it and you're allowed; record your shops. When I started I always did it when I was allowed. I also have a steno pad to write all my notes as soon as I can get back in the car.
I've been known to write narratives in Word as drafts and leave them for a couple of hours if time allows and reread later. These drafts help me with telling the story. They also help with the shops that have more negatives than positives.
Eventually you will figure out which companies like you to write the story and the others that want the 'Jack fell down the hill.' sentences.
It just takes time. Don't get frustrated. We're here to help if we can. This is one of the most supportive forums I've ever been privileged to be a member.
Live your life in such a way that when your feet hit the floor in the morning; the devil shudders...And yells OH #%*+! SHE'S AWAKE!