I do have a bit of advice in regards to formatting dialogue. This is entirely constructive, don't think I'm picking on you. When it comes to dialogue, it is correct to end your sentences with a comma instead of a period (unless it is at the end of the paragraph). The difference is slight but makes a difference.
Ex.
Wrong: "It's not all bad." Jim said.
Correct: "It's not all bad," Jim said.
Furthermore, with each change to a new speaker, you should start a new paragraph. For grammar reasons. And so you don't have crappy sentences that are hard to follow.
Ex.
Wrong: "Won't you just leave me alone?" Tina sighed. "Not until you give me an answer," grinned Stephen. "Fine," Tina groaned, "I'll tell you..."
Correct:
"Won't you just leave me alone?" Tina sighed.
"Not until you give me an answer," grinned Stephen.
"Fine," Tina groaned, "I'll tell you..."
These are two very important rules to follow in the structuring of dialogue, and they will help your scenes flow naturally if you do it right. If your characters are given enough, well, character, then you can take it a step further and stop constantly referencing people in a scene. Can also give off a back-and-forth effect if short enough.
"Give me the stone," the wrinkled old man wheezed. "A child such as yourself should not play with such things."
"What claim do you have on it, ancient one?" You retort.
"You try my patience, boy."
"And you mine."
A toothless snarl transforms into hoarse laughter. "Oh, you're quite the cheeky one! If that's the case, then—" The old codger leapt forth, surprising you with his agility and vigor, snatching the smooth, ovular rock from your hands, then dashing off with a cackle. "Try to keep up!" he taunts.
You were beginning to doubt you could after such a display, but you still chased after him...
Anyways, there you have it. Hope this helped some.