Here are the contexts of the quotes tweeted from September 11 through September 17, 2014. The first six are from Beauty and the Werewolf, by Mercedes Lackey.
“It’s not just what you are good with. It’s what you’re good at.” Sebastian to Bella, when suggesting she might be a better sorceress than a witch.
“A whistling girl and a crowing hen always come to some bad end.” The housekeeper’s admonition when she used to catch Bella whistling.
“A whistling girl and a wise old sheep are two of the best things a farmer can keep.” Bella’s retort to the housekeeper.
“War is never good for trade.” Bella remembering her father when a war seems imminent. The arms trade is an unfortunate exception.
“Curses don’t die with their maker.” The magical distinction between a spell and a curse.
“As long as there was a chance I could help you by staying with you, that’s what I had to do.” Sue Ann Bowling, Tourist Trap. Roi’s statement to Penny when she wonders why he didn’t save himself by teleporting away from the sailboat in the squall.