Rules for Life, by Darlene Ryan

Izzy's Mom left her with a rule to cover any situation, and in the absence of a living mother, these rules guide Isabelle through life. But when her father decides to remarry, and Izzy's older brother falls off the wagon, the rules don't seem to cover the situations she is facing.

A rather irregular and uneven book, with trouble creating an authentic voice. There are times when Izzy seems too petty to be the older high schooler she is supposed to be, and other times when she is far too worldly and well-spoken to be a plausible adolescent. And the story plods along in somewhat melodramtic fashion from one crisis to another, without large amounts of linkage between events.