Welcome to Mac Mavericks

Rebuild the desktop regularly (weekly is a good idea, more often if you are experiencing system crashes.) Hold down the COMMAND and OPTION keys as the computer is starting up; continue to hold both keys down until you see a dialogue box asking if you want to rebuild the desktop.
The COMMAND key is somtimes referred to as the OPEN-APPLE key and is located between the OPTION key and the SPACE-BAR.

Use Disk First Aid regularly (and/or Norton Utilities). This should be done every week, more often if you are experiencing system crashes.
Disk First Aid is a free utility that ships with every copy of the Macintosh Operating System. It is included with the Disktools disk or disk image.
You should always have a current Disktools floppy disk ready for your particular model of Macintosh. This disk will allow you to start your computer if the system software on your hard drive fails to start your computer.
Running early versions of Disk First Aid from the hard drive will allow you to detect problems, but they cannot be corrected while the computer is running the system software from the hard drive. Starting the computer from the DiskTools disk and running Disk First Aid from the floppy allows for problem correction.
The very latest versions of Disk First Aid (8.2 or later) can be run from the bootup drive and correct problems on that drive. MacOS 8.1 or later is required to run Disk First Aid 8.2 or later.

Optimize regularly. This should probably be done every month, more often if you move a great deal of files on and off your hard drive.
#Clean your mouse regularly. This should probably be done every month.
While the computer is shut down, open the cover on the bottom of the mouse and remove the mouse-ball. Use rubbing alcohol on a cotton swab to clean the rollers that make contact with the mouse ball. If fibers have become wrapped aroung the rollers, use tweezers to remove those fiblers. Do not use the rubbing alcohol to clean the mouse ball, since alcohol can dry out rubber and cause it to crack. Instead, use a clean cloth and tap water to clean the mouse ball. When all of the components have dried out, reassembe the mouse.
Do these all of the time:

Keep sufficient space open on your drives and disks.
The system creates invisible files when preforming certain tasks, such as printing, that still require space on the drive even though the file is invisible.
50 MB of free space should probably be considered minimal. 100 MB is probably ideal for using basic programs (i.e., email, wordprocessing, spreadsheets.)
The use of virtual memory may require free space in addition to the amounts mentioned in the previous paragraph. Some programs, most noticeably Adobe Photoshop, have their own virtual memory scheme built-in.

Run up-to-date virus checking software.
Most commercial virus checking programs produce monthly updates.

Keep drive formatting software up-to-date and update the drivers on the drive.

Keep a boot-up disk with Disk First Aid handy.

Install new software with extensions turned off.

Keep your software versions compatible with your System Software. There are no great tips to pass along for keeping track of software versions and their compatibility with various versions of the operating system. Combinations of asking other users, checking web sites, or calling the company that supports the software will probably be needed.

Don't put the System Folder inside another folder.

Don't move or rename any files or folders within the System Folder.

Don't rename the folders created when applications are installed.
Updaters often look for folders by the same name given to the folder at the time of the original install. If you rename that folder some updaters may refuse to work since they cannot find that particular folder with that particular name.

Don't move the application outside the folder.
Some applications need to be located in the same folder as their support files to work properly, so it is a good idea to keep them in their original folder.
Create aliases to applications if you want to start them from another location (from the Apple Menu, for instance.)