fuel consumption

hi guys. any help on this one will be appreciated. i have a 1997 318is, she is stock to the max, only thing ive done is some stickerbombing. my problem is that this car seems very thirsty.... my average consumption is roughly 10,5 km per litre. is that fair or not, if its a bit high, what can i do to try rectify the problem? thanks a lot.