To start things off I will touch on something that often gets over looked. Services. Both modern Windows machines and Linux machines have services of some sort that get started with the machine. Unless you have changed or disabled the ones you do not use you are taking an unnecessary risk.
To disable a service is normally fairly simple. With a Windows machine you can left click on the My Computer icon and select manage. On the left hand side of the window that pops up you will see Services. After clicking on that you will basically be presented with a list of services, their status, startup type and a description. Go through the list and disable anything you are sure you don’t need. If you don’t know read the description. If you still don’t know leave it alone.
I can not tell you how to disable services on all Linux distribution as there are a few ways. At one time I could tell you how to do it on Fedora Core, Gentoo as well as a few others. Thing is I finally found a distribution that suits me and I have been using it for far to long to try to cover anything else. The distribution is Slackware.
On a Slackware machine the start up services are controlled by files in /etc/rc.d . You can easily disable a service or daemon by removing the executable bit, or “chmod -x filename”. If you are unsure of what you need read the file itself. They are very helpful.