Anyway, probably the most rookie mistake I see (other than grammar or spelling) is what I call the Taking Head Syndrome.
|Burnin' down the house!|
“On the ship,” David said softly, giving her a reassuring pat on the shoulder.
“Oh," she sighed, rolling over to her side. “Okay then.”
“Hungry?” He jerked a thumb backward in the general direction of the kitchen.
Jessica drew her knees up and wrapped her arms around them. “Not really.”
This was written about four years ago, and so it's a little awkward. It is, if anything, too animated. If there was storyline before and after this scene it would flow better. Still, it gives an example of where they are, what's going on, and possibly how the two characters are feeling.
Too many people get caught up in writing dialogue because it's easy to go back and forth in a conversation. However, conversations are boring if your characters have their metaphorical hands tied to their backs and their feet are glued to the ground.
A good way to get a visual of this is to watch two people having a conversation. Watch what they do. They walk, or move their arms, or smile, or nod. People are animated creatures, and animating your characters helps to breathe life into them.