I don't want a boob job but i would like to make them bigger somehow. how?

Why?: Why do you assume that this is something that you need to be attractive. Your personality and confidence will make you a more disable partner than uplifted breast. Talk to some body that deals with body image issues, a counselor. Or go find a plastic surgeon that will help you with that. Would suggest the former rather than the latter as step one. Exercises might help.

Breast size: The breasts enlarge naturally with weight gain, puberty, pregnancy and breast-feeding.

Think injection: Autologous fat transfer involves taking fat from donor site and injecting into areas for enhancements. Current research is looking at taking dermal fillers and injecting for same.