A lot of people feel like urban fantasy is a shortcut that gets you around world-building, because it's set "in the real world." But it doesn't really work that way, as I found out. You have to come up with just as consistent an internal cosmology and magic system as you would if you were writing high fantasy.
Cassandra ClareAnd then she said nothing else, for Henry put his arms around her and kissed her. Kissed her in such a way that she no longer felt plain, or conscious of her hair or the ink spot on her dress or anything but Henry, whom she had always loved. Tears welled up and spilled down her cheeks, and when he drew away, he touched her wet face wonderingly. "Really," he said. "You love me, too, Lottie?
Cassandra ClareMagnus stood up and went to the window. He pushed the curtain back, letting in just enough light to silhouette his hawklike profile. "Blood," he said, half to himself. "I had a dream two nights ago. I saw a city all of blood, with towers made of bone, and blood ran in the streets like water." Simon slewed his eyes over to Jace. "Is standing by the window muttering about blood something he does all the time?" "No," said Jace, "sometimes he sits on the couch and does it.
Cassandra ClareYou are aware that the sale of liquore is currently against the law." Edgar went on, "but I suppose that is why you enjoy it." "Everyone should have a hobby or two," Magnus said. "Mine just happen to include illegal trade, drinking and carousing. I've heard of worse." "We tend not to have time for hobbies." Shadowhunters. Always better than you.
Cassandra Clare