How do you make your voice stronger/ less operatic?

ok so i've been taking voice lessons for about a year and a half. im 16 and I feel like my voice is still kind of weak... it has a pretty tone to it and I can definitely tell that it has become stronger but i have hardly any vibrato in my voice and I would just really love for my voice to be more powerful. i know how to sing using the diaphram and using support. does anyone have any idea how to make your voice stronger, get more vibrato, oh!! and also does anybody kno whow to make your voice less like, operatic if you know what i mean...like less choir voice more realistic i guess. like i dont know kelly clarkson or something...im not saying i want to sing just like kelly but kind of like her kind of voice i gueess. thanks!!