The most important tool is a good text editor with syntax highlighting.
Download the EDITOR SYNTAX BUNDLE from SF - Syntax Bundle July 30th, 2013
Some good choices out there that have been used by previous data monkeys:
- WINDOWS SYSTEM
- OTHER SYSTEMS
Most of these have PCGen specific syntax highlight files (Links to them are on the setup page for each editor). There are other good text editors, but you would need to create your own syntax highlight file for them.