“Know when to hold ‘em; know when to fold ‘em.” That’s good advice for poker and good advice for writing.
There’s a simple rule to remember — if it doesn’t advance the plot, get rid of it.
Take the following passage from the rough draft of Chapter 27 of Power of the Mages:
He had a pretty good idea of the direction from his multiple earlier sensings of the power, so he walked in that general direction. His path took him through the center of the nearly deserted city. Only a few of the shops were open, and those saw little custom. Even with the relative coolness of the day, the sun shining on Xan’s head caused the mass of curls atop his head to become a discomfort.
“I hate my hair. Brant’s and Dylan’s grow down. Mine grows straight out.”
He searched the area for an open barber but didn’t find any. He did, however, spot an open clothing boutique down an alley that sold men’s hats. Ducking in, he quickly selected a wide brimmed cover that didn’t look too hideous. The flat black color didn’t stand out, and, aside from a black band, it had no ornamentation.
As he placed it on his head, the shop’s proprietor approached. “That looks perfect on you, young sir. For the low price of one silver, you’ll have the young ladies falling all over you.”
Xan chuckled despite himself. “I seriously doubt that, and, if it’s more than two coppers, I’ll be putting it back on the rack.”
He didn’t hear the man’s response because he sensed the magic use again. He pulled five coppers out of his pocket, generously giving one more than what he figured was a fair price, and handed them to the older man. No complaints followed him out of the shop.
As he rushed down the alley back to a small square with a fountain depicting some form of imagined sea creatures, he saw two men walking away from him. Something about their walks stood out to him. He looked at them magically. Both glowed with power.
When I read back over this to edit it for the 2nd draft, I thought, “This is dreadful. Why did I even write it?” It relates nothing about the plot since the hat never comes into play in any meaningful fashion, and there’s no tension. I finally figured out that the entire passage is there to get Xan out of the way of the two catcher’s men so they don’t see him. There’s a much easier way to do that. See the new version:
The winding streets confused him, forcing him to backtrack several times. As he entered a small square, he sensed magic use again. Trying to get a better orientation, he rushed down an alley. When the narrow lane intersected a road, he felt the mage to his right, but movement to his left drew his attention.
Two men walked away from him. Something about their gaits stood out to him, so he examined them magically. Both held power.
That’s 220 fewer words to accomplish the same plot goal.
Often, the best way improve your work is by deleting the stuff that doesn’t belong.