Pick the "spin" ISO you want (eg, KDE, Gnome, Xfce ... etc) from the appropriate site and download it. Create a bootable DVD or USB (This what I do) then Install., it's pretty easy. Of course it should go without saying but backup and make sure you have documented all customisations which is user info, repos, wireless password (if appropriate), then when the install is finished (usually within 20 minutes) add those customisation and any additional software.
As far as partitioning this new distro is simplicity itself and I actually use LVM to create the appropriate volumes and then use ext4 for my file-system.
I did have one major issue which was not the fault of Fedora and that was a faulty sector on my disk. A complete reformat fixed that but my recovery took a few hours. If I get any more bad spots on my disk I will have not choice but to replace it.