What do famous people have to do to become famous?

Famous people become famous by showing that they have talent. In order to do that, they have to find a talent scout to show them that they have the talent that it takes to become famous. You can be the best carpenter/locksmith/dentist in the country, but unless someone of some fair influence makes it known publicly, you will mainly be known to your local clients. Even in show business, you generally need some 'lucky break' to do well.

Susan Boyle is the classic example: she was not 'discovered' until she was 48! If it was not for such a show as 'Britain's Got talent' rising more recently, she would have remained totally unknown in the back blocks of Scotland. Think how many previous Susan Boyle's the world has missed out on!!
Even Justin Bieber was not genuinely famous until he had been discovered and promoted by other famous people.

Nevertheless, there is a start to it all; and that start is just plain HARD WORK and being humble enough to be able to be taught and to learn! So first get an acting coach or singing coach. Practice a lot and go for try outs. Try American Idol OR America's Got Talent. Look up any roles in movies for audition. Never give up and keep your head held up high. Really, although you might like the call of "fame" itself, your prime motivation for what you are doing is simply that YOU LOVE IT. If you don't love it, you will never do as well as others who do. So if you are mainly in it for the possible name you make for yourself, you can probably give the idea over before you start.