First of all, some warnings from an obsessive journaller: Don't trust words. Words often suggest a neat solution where there is none, seductive symmetries (e.g. two sides of the same coin) that only work when you ignore certain other factors, or cool-sounding narratives (e.g. Greek myths) that don't fit the actual facts. Another mistake I've often made is treating allegories or quotes as proofs when they can be nothing but illustrations. You can lead yourself a merry dance with words.
Second, and this ties in with my first point, is that the Shadow is only one concept amongst many.
would be another method of cataloging the self. For myself, I've found that dispassionate introspection works best, i.e. looking inside myself without judging and without expectations.
Third, be prepared to discover that some character traits you have hitherto regarded as beneficial or even virtuous (i.e. definitely not part of the Shadow), or the concept of your 'real me', can come into question. One example I've discovered recently was 'righteous anger' - Abrahamic religions tend approve of it because of their irascible Old Testament god but for Buddhism, it's still anger and thus poisonous for the mind. 'Moral indignation' may be another example.
Fourth, I think it's a bit dangerous to subsume all kind of disparate negative currents under one heading and then start worrying about nothing but
the Shadow bogeyman when in reality, varied and indepent forces may be at work somewhere deep down. It's better to look at those currents one after the other and see if they're in fact related.
Five, insights do not necessarily mean you've got a handle on things. It's been incredibly frustrating for me whenever I finally found (or believed to have found) the cause of some emotional problem and discovered I couldn't do anything about it. Psychotherapy's implied promise of salvation is that genuine healing will only start once you've brought some deep-set fear, childhood trauma, etc. out in the open. This may be true for some cases, throw you into an endless loop of narcissistic rumination in others, or not work at all. Again, it's words that suggest the feasibility of emotional engineering (the Buddhist stock phrase of "Cultivate compassion" as a panacea, for example) that may not exist, or at least not as a straightforward method.
I don't trust words, and I write and I write…