Download speed limited - How to unlimited

I already have a Linux CentOS server.
I am looking in finding out how can I raise the download limit of my server.

The users can download files from server with the maximum speed of 300Kbps. The server's speed is 100mbps.

Does anyone know how can I do this?

It depends on multiple factors:

1. Does the server have a dedicated line or is it shared (i.e.: connected to a switch)?
2. Where they are located in relation to the server. Just because you buy a server in Japan that promotes 1Gb/s speed doesn't mean someone in New Mexico is going to get anywhere near that.
3. What web server is being ran?
4. What protocol is being used to transfer the file?
5. Is there a firewall involved anywhere between the user and the file?