You have two choices:

Install packages

For Fedora, see Koji http://koji.fedoraproject.org/koji/packageinfo?packageID=14565, or if your mirror is updated, just "yum install linux-user-chroot".

Build from source

As of this writing, OSTree depends on (unreleased) GLib 2.36 and libsoup from GNOME 3.7 development. You can use use Jhbuild to build as a user.

Here's a sample ~/.jhbuildrc:

checkoutroot = '~/src'
prefix = '~/build'
skip = ['nss', 'libxml2', 'nspr', 'fontconfig']
moduleset = 'gnome-world-3.8'
ignore_suggests = True

The ignore_suggests part is strongly recommended.

Once you have jhbuild set up:

 $ jhbuild build ostree