Sometimes a child like this will blossom with a short round of individual counselling - why don't you ask her if she'd like to try that? If she refuses, then the appropriate parenting techniques involve reducing criticism and increasing positive feedback and unconditional positive attention while also using "emotional coaching" (see "Raise Your Kids without Raising Your Voice" for details on how to apply these strategies). Keep in mind that it is not all up to you at this point; your daughter has to find her own way in creating a satsifying life and a more or less permanent good mood. You can bring home some self-help books that share strategies about this, but you can't make her read them. Sometimes it requires more growing up time until the person decides that SHE wants to work on it.
Sarah Chana