I very often mention using a form of divination to check in before starting on a course of magical work, or in choosing which condition formulas or herbs and curios would be best for a particular spell. Divination is one of the topics that seems very daunting to many just beginning to practice, and even to some who have been practicing for a while.
The tarot can seem overwhelming with its seemingly endless layers of complex symbolism. The I Ching can seem confusing with all its yarrow sticks or coins and determining whether a line is open or closed. Geomancy is likewise complicated, and astrology has so much going on. It can seem very daunting to learn a system to serve you in your magical practice.
As amazing as those forms of divination can be, you don't have to learn one of those, especially if it seems that you may not be all that gifted as a diviner. But that doesn't mean that you are stuck always shooting somewhat blind when doing spellwork, or that you are stuck relying on other practitioners to do divinations on your behalf. Finding a yes/no-type oracle can be very simple, and pendulums fit the bill!
I will admit to being a bit of a late bloomer on the divination front due to the math and statistic-type feel of many divination systems (it's just the one area of my brain that is very weak - so numbers, degrees, etc just hit a 'dead spot' in my melon), and with getting caught up in the Qabalistic and astrologic and Jungian symbolisms within the Tarot which for a long time kept my intuition from being able to access the cards. Having a yes/no oracle was a real boon during that time, and once I started using one my success rate on spellwork went through the roof! While I read tarot without issue now, I still use my pendulum almost every time I'm picking ingredients for an oil or herb blend, or when choosing ingredients to go into a bottle spell or mojo bag. It's quick, easy, and accurate.
Dowsing using a pendulum can start off as easy as learning a "yes" and "no" swing, which can be invaluable in occult practice. Pendulums are also very flexible and can easily be tuned to doing much more complex work, while still using the extremely simple back and forth swing as an indicator, rather than relying on layers of symbols.
Rather than going into all the details here as to how to get started using a pendulum, I will point you to a truly excellent resource that is quick and easy to read, extremely thorough, and provides simple exercises to get you started, as well as more intermediate and advanced lessons and sample pendulum charts for moving forward. You could easily be skilled enough to divine on the outcomes of your ritual and spellwork within just a few day...rather than weeks or months (or years) spent mastering a more layered system such as the Tarot.
The Letter to Robin is an amazing site that you can read online or print out as a PDF to work with at your leisure. It was written by a professional dowser in answer to some of the most common and basic questions about getting started with using a pendulum. I highly recommend it to anyone who wishes to learn pendulum dowsing.
Now - I am in no way saying that a yes/no oracle replaces divination methods such as the Tarot or I Ching, but it is a truly excellent option for those who wish to become skilled at basic divination in short order. And if you enjoy the pendulum, you can certainly learn to do MUCH more with it over time. The Letter to Robin can help you through it.