It's always good to clear off unwanted files or applications your not using to free up some space.
This helps speed the PowerBook up a little more. Save on the file indexing.
The safest method is to simply used uninstaller that came with the applications.Most applications don't have uninstall files, so simply placing them in your trash and emptying it is more than suffice.
stay way from deleting anything in the 'System' folder and you should be just fine.
To add to the suggestions from Knuclesmac keep plenty of free space on your HD, don't keep files on the desktop, don't install pointless bolt-ons and gizmos, verify the HD with Disk Utility every few weeks, avoid dodgy websites. If you sleep it between uses shut it down once a week or when it's not going to be used for more than a day or two.
A couple of things I do for our G4 Macs that have helped:
1) Don't leave Dashboard running: Some widgets reman active in the background when not in use, and use processor cycles. Widgets that have to "phone home" to a server are the worst. Some recommend disabling Dashboard completely but that's not needed. Get the widget "DashQuit" from here:
It puts a little "Off" switch among your widgets that turns off Dashboard when you are done using it.
2) If you have Safari installed, you need to neuter Tops Sites. If not, one of its background processes, 326 Safari Webpage Preview Fetcher, will eat cycles like a velociraptor in a meat market. It stays active even when Safari is shut down. These steps don't "remove" Top Sites, they only remove the opportunities for it to get invoked, which causes the cycle-eater to run.
a) Open Safari Preferences and, on the "General" page, make sure all options for page or tab opening, including your home page, say anything other than Top Sites.
b) Now got to Safari Preferences > Bookmarks and uncheck "Include Top Sites" from the Bookmark Bar options. That removes the icon from the bookmark bar so it doesn't accidentally get hit.
c) Now to clean out what built up before the settings change. Do Safari menu > Reset Safari... to get a window with options.
Set yours like the example and hit the Reset button,
If you really need Top Sites after doing this, it's always available from the "History" menu. If you invoke it, you will need to restart the computer and do Step C again to keep the background burglar from stealing processes