How can u become a better singer then what u already are?

I always sing in tha car bathroom werever i am..i think im a good singer but wen i record myself. my voice is not wat i hear..i seem 2 get aggravated..i want to become a good singer to hit some notes tht i kant hit now..i noe some ppls voice go with diff types of music..im goin 2 start puttin some vids on youtube..pllzzz i just need some tips on how to make my voice good and maybe some excersies