You can't just be an actor and become famous the world doesn't work like that the odds of an agency excepting you and making you famous is under 1% and dude fame isn't as fun as it seems after a while you get annoyed seeing yourself on tv every day. You have to get lucky youtube it is a .5 % chance you would get famous off of there. You need to know someone who works as a producer. Find some one who works in the field and start from there work at commercials
Connections always help of course, most actors and actresses start up through family or friends.
My best advice would be to just go to as many auditions as you can and start small to build your name up. Do plays, then commercials, voice acting, unmentioned roles, and just claw your way up the chain.