This is a common tool for improving performance, yet one that is often overlooked. Some 'extra stuff' to look for:
Graphical desktop
Do not run graphics there they are not absolutely required, especially on servers. To avoid running the desktop software, open the /etc/inittab file with your preferred text editor and locate the following line:
id:5:initdefault: ...[output truncated]...
This setting changes the runlevel that the machine automatically boots into. By default, the runlevel is 5 - full multi-user mode, using the graphical interface. By changing the number in the string to 3, the default runlevel will be full multi-user mode, but without the graphical interface.
id:3:initdefault: ...[output truncated]...
Sendmail
Unless you are actively using Sendmail on the system you are tuning, disable it. If it is required, ensure it is well tuned or consider moving it to a dedicated machine.
Remote Procedure Calls (RPCs)
Network File System (NFS)
Mouse Services
If you are not using Gnome, then you probably won't need a mouse either. Remove the hardware and uninstall gpm.
Remember to also check your third party applications, and any components added by external hardware vendors.
For more information, or for further reading, the following man pages are related to the information given in this section.
rpc(3)
nfs(5)
gpm(8)