Two things, as I kept saying and saying,
1- The default ISO of the stock camera application is too high. Result- blurry photos. So either manually decrease it or use third party app like Camera Zoom FX.
2- The LED flash is terrible. In dark you will notice that it ain't strong as it should be. Under low light you should use 'low light' mode, always, that'll cause higher ISO photos causing grainy shots however.
The quality of the Camera sensor is below average overall, so don't expect great results.
Personally I have my D90 and 550D for basic stuffs, that's why I don't give a damn about this crappy camera, but I feel sad for the people who are forced to use this camera often.
Swyped from my GT-N7100