In theory, all you need to do is to setup rpm build tree, drop-in spec file and sources, source tarball named according to spec file, bump the version and reset the rpm release number.
While you can use rpmbuild directly to build the package, it is expected that you install build dependencies into your base system. The preferred solution is to use mock that builds the package into a chroot environment using a source rpm package. Rpmbuild is then used only to build a source package. That way you don't clog your base system, and have a more consistent packages since you test build dependencies as well.
If you want to know more about it, I suggest you start from basics of how rpm building works and then move onto Fedora specific documentation. Something like this should give you an idea: http://www.tldp.org/HOWTO/RPM-HOWTO/