Donald Michael Kraig has a brief piece on his blog about why magic fails. Aside from the usual advice about keeping journals and whatnot, Kraig has an interesting perspective about filling the voids that your magic creates:
One of the things that they don’t talk about in NLP is that feedback isn’t enough. You also must be able to understand the feedback. One of the typical examples of this is questions I receive about a certain type of magick that doesn’t work. Specifically, I’m talking about getting rid of something you already have.
Most of the time, when people talk about banishing rituals, they’re talking about keeping something unwanted away. However, some people want to do banishings to send away something they possess but is unwanted—banishing an illness, banishing poverty, banishing a boyfriend, etc. Very often these either fail or are only temporarily successful for a simple reason. This reason was first put forward by Aristotle (384 b.c.e.–322 b.c.e.) when he wrote “horror vacui,” usually translated as:
Nature abhors a vacuum.
Simply getting rid of something you have isn’t enough. It leaves an empty space and something has to fill it. Often, that something is simply what was there before. Banish a bad habit and it fades away—for awhile. But then it returns.
The solution becomes obvious. If you’re doing magick to banish something you currently have you must replace it with something else. Not in the future. Not in a second spell or ritual. As part of the magick you are doing.
An interesting perspective, at least for the specific area of banishing magic.
For the record, though, I still regard Phil Hine’s lecture on Rites that Go Wrong to be the seminal work on magical mistakes, failures, and mishaps.