On a Red Hat Enterprise Linux or Fedora (or compatible) system execute
$ vim example.spec
This will create a new file with all the important sections and fields
already there. The template used is /usr/share/vim/vimfiles/template.spec
and is part of the vim-common RPM package.
This is very useful trick which I didn't know. Until now I always used the spec files from previously built packages when creating new RPMs. This wasn't as fast as creating a template and filling in the blanks.
For a detailed description about recommended RPM build practices see the Fedora Packaging Guidelines.
There are comments.