Mac Care and Maintenance
- Clean up and Revise a Sluggish Mac | Lifehacker
- Speeding Up Your Mac | MacWorld
- Monitor performance and available disk space:
- iStatPro - monitor memory hogs such as Dashboard widgets. You can also try Activity Monitor or the shell utilitiy top.
- Disk Inventory X - keep disk less than 2/3 full and use this app to find out where you are spending your space.
- Go monolingual - reduces disk usage and increases performance of Safari
- remove Flash - a known memory hog
- Mac Care and Maintenance blog post | AstroBetter - especially the comments