These are basically the same things that make good code.

• Organising files = project structure

• Resource & layer naming = variable naming

• Using templates & sharing common elements = DRY

• Keeping vectors when rasterising = keeping source code when compiling

• Minimising filters, blending modes, colour overlays, etc. = KISS

• Grid = idioms and “design patterns”

• Understanding licensing = understanding licensing

• Proofreading = code review

• Browser compatibility = platform compatibility

• Conservation of file sizes = consideration of performance