Im not a professional astrologer, but I have my own interpretations, but perhaps Lydia can add her professional incite to this matter.
I have a planet I'd like to manifest the constructive qualities of in the twelfth as well, so lets see what we can do.
First, the twelfth is naturally ruled by Pisces, which in turn is ruled by Neptune.
You have to see where Neptune is in your chart, what sign its in is the kind of mood it presents, what house its in may involve what parts of your life get in the way of your spiritual talents, or even what benefit it in some cases if the planets Neptune is near are such as the Sun or Jupiter.
With that, is Neptune aspecting the the planets in the twelfth house itself, or Saturn which can both add to the possible suffering or constraint on your spiritual freedom?
The typical opposite to the twelfth house, Pisces, and Neptune is the sixth house, Virgo, and Mercury.
Mercury is the technical, sophisticated, rectifying, organizing, healer type which evidently a lot of Piscean energy requires to counter balance its ailments.
Look at what planets are in the sixth house, which relates to possible ailments or things you need to build a routine around to stay healthy (possible challenges of the health or your daily livelihood in work or home).
Look at any planets in Virgo, and where is Mercury located for the kind of energies needed to set you on a path free from spiritual constraint or self delusions leading to such.
I hope I gave some useful tips, and as I said hopefully Lydia can elaborate a more experienced one on one with you about this issue.