Following this guide has made a great difference for me on old hardware, using an old Acer Aspire One ZG5 netbook computer on Ubuntu 12.10, is now much faster. While it's not super-fast, I do use this little old computer for most of the command-line work of configuring my server, the Gnome desktop environment for writing this website, and general normal use (emails, web etc...).
Ubuntu's documentation website recommends the most suitable version of Ubuntu for specific hardware models, so for Acer Aspire One models see: help.ubuntu.com.
This guide has been adapted and updated for Ubuntu 14.04 over here.
This will enable us to simplify the user desktop environemt.
~$ sudo apt-get install gnome-shell
Select LightDM Display Manager if prompted
Now logout, and upon logging back in choose the "gnome classical no effects" desktop environment.
Unity Destop Environment left, Gnome Destop Environment right:
Unity is the flashier looking desktop environment, and Compiz adds the fancier swooshy 3D-type effects, both of which just slow your computer down.
~$ sudo apt-get remove unity
~$ sudo apt-get remove compiz
Synaptic is again, more lightweight than Software Center.
~$ sudo apt-get remove software-center
~$ sudo apt-get autoremove software-center - possibly not needed
~$ sudo apt-get install synaptic
Install Gdebi package installer:
~$ sudo apt-get install gdebi
This small program announces social media notifications.
~$ sudo apt-get autoremove indicator-messages
~$ sudo apt-get autoremove telepathy-indicator
Deja-dup is just a backup tool.
~$ sudo apt-get autoremove deja-dup
Zetigeist logs and records file use history, to create a "recent files" list.
~$ sudo apt-get autoremove zeitgeist-core
A more lightweight media payer.
~$ sudo apt-get remove totem
~$ sudo apt-get remove rhythmbox
~$ sudo apt-get install smplayer
~$ sudo apt-get install gconf-cleaner and follow the steps.
Now run Gconf-Cleaner.
~$ sudo apt-get autoclean
Aside from it's amusing name, Bum allows you to disable unnecessary system services.
~$ sudo apt-get install bum
~$ gksudo bum