Subscribing to packages on the PTS is really useful to stay informed of everything happening with those packages. Unfortunately, managing your PTS subscriptions is really a challenge. Here is how I proceed to subscribe to packages I forgot to subscribe after uploading them:

• To get the list of your subscriptions, connect to master.d.o, and run
  /org/packages.qa.debian.org/bin/get-summary-subscribers.pl | grep your@email
  That’s also a way to know who is interested in your packages. :-)
• You can use UDD (from master) to know the list of packages you should probably be subscribed to, that is, packages you maintain or co-maintain in sid:
  psql -A -t service=udd -c "select source from sources
where distribution='debian' and release='sid'
and maintainer_email='your@email'
union select source from uploaders
where distribution='debian' and release='sid'
and email='your@email';"
• You can them use combine to find the packages you should subscribe to, and mass-subscribe using the email interface.
• Then, you are done, or almost done: mass-confirming PTS subscriptions is a PITA because of #340863.