An improvement over direct editing on the server is to edit the files locally on your PC and then use FTP to upload them to the game server. This video tutorial will show you how.
The transcript is available here.
For links to the code editors mentioned in the tutorial, check out Code Editors.
Editor’s Note: The video mentions the “next tutorial” being about GitHub, but that’s not true any more. You can learn about using GitHub after you’ve learned a bit more about Ares Code.