Hey,first,if you feel called by God,your half way there.
Second,practice,practice,practice,and be honest with your self.If someone helping you on your vocals says your flat,or sharp,or need a vocal coach,dont get mad,just listen,follow the right steps,and then once again,practice,practice,practice.I mean if you really love to sing,you put your all into in,from the heart all the time.There's people out there in local chiors,that sing just as well as the stars,but do you want to be a star??or sing for the glory of God??? .
And yes,the same goes for musicians.Also remember music is a ministrey too,so always try to start in prayer..