If you want to try Linux, number one have a spare machine. Also think about the machines specs, like if it is pretty old maybe look at a light weight distro like puppyLinux, Debian is also good on older machines. First thing to do is take your time and think what you want to use it for. If it is bleeding edge graphics an art distro is better preferably one with good packages preinstalled. Really take your time and be prepared not to get it right the first time.