In my opinion, these are the "rules" to applying logic to magic:
1) If it's too good to be true it probably is. This is true everywhere else in life, and it's certainly not an exception within magical practices.
2) While magic might be utilized to influence things within one's life (to what extent is quite debatable), it does not provide shortcuts. You still have to work towards your goals, and you must be ready to act upon the opportunities as they become available.
3) Apply a healthy dose of cynicism. No, I don't mean that you must doubt everything off hand, but you should try to find a logical, reality based reason for any results that you experience far, far before you leap to the conclusion: "Magic!"
4) Spirits and the like are not as common as the number of people shouting "I conjured a demon!" or "I'm haunted!" or any number of similar claims would indicate. Most of the time it's just overactive imaginations, and even when it's not people are far more likely to be overreacting than to be calmly observing and recalling any such incident. Mind you, it's not their fault. Witnesses to traffic accidents, crimes, and the like similarly almost always have conflicting reports because, frankly, the mind is prone to panic, the quirks of individual perception, and the nature of memory result in everyone experiencing things differently, and recalling things yet more differently. This is even more true when some trick of light or a feeling of unease leaves the observer spooked.
5) Which leads me to the last point. Just because you experience something, and it is real to you, does not mean that it will be real and true to another person. Such experiences are commonly called Unverified Personal Gnosis. This means that your experience, while enlightening to you, is still something just observed by you. What you experience has likely not been observed in a closed, controlled environment allowing one to readily dissect the results and prove them to be true without a doubt. Beyond this, magical "energies," spirits, and other such things that are observed in such situations do not generally manifest light, sound, or any other such readily explained means of perception. They are more subtle, and observed through a number of other sensory experiences that the mind then creates images of, sounds of, etc. to explain what it has perceived. Thus even if you and another person experience the same thing there is a good chance that it will be a bit different for both of you. The point? What you experience is not the gospel truth, and will often sound crazy to everyone else even if it helps you on your own individual path.
There's more (there's always more) but I'm going to stop babbling.