All patches in Fedora spec files SHOULD have a comment above them about their upstream status. Any time you create a patch, it is best practice to file it in an upstream bug tracker, and include a link to that in the comment above the patch. For example:

# http://bugzilla.gnome.org/show_bug.cgi?id=12345
Patch0: gnome-panel-fix-frobnicator.patch

The above is perfectly acceptable; but if you prefer, a brief comment about what the patch does above can be helpful:

# Don't crash with frobnicator applet
# http://bugzilla.gnome.org/show_bug.cgi?id=12345
Patch0: gnome-panel-fix-frobnicator.patch

Sending patches upstream and adding this comment will help ensure that Fedora is acting as a good FLOSS citizen (see Staying close to upstream projects). It will help others (and even you) down the line in package maintenance by knowing what patches are likely to appear in a new upstream release.

If upstream doesn’t have a bug tracker

You can indicate that you have sent the patch upstream and any known status:

# Sent upstream via email 20080407
Patch0: foobar-fix-the-bar.patch
# Upstream has applied this in SVN trunk
Patch0: foobar-fix-the-baz.patch

Fedora-specific (or rejected upstream) patches

It may be that some patches truly are Fedora-specific; in that case, say so:

# This patch is temporary until we land the long term System.loadLibrary fix in OpenJDK
Patch0: jna-jni-path.patch