how2b famus?
There are a few ways.
1. Make the game.
2. Make add-ons that a large amount of people want to have. (Or just be a pro codar/modelre)
3. Host a popular server often.
4. Post on the forums frequently.
5. Make pro builds frequently and show them on the forums.
6. Create a successful external service. (Like Kalphiter's hosting service)
7. Make friends with someone popular. (Only works on some occasions)
Feel free to add to this list anyone.