In Lessons of the Fundamentals of Go Kageyama repeatedly emphasizes the importance of going back to the basics in all things: from Go to Baseball to Cooking, saying of Go that:
When a beginner learns the game, the first things he should learn are the fundamental skills. When he advances to the point where he begins to think of himself as a strong player, the thing he needs to do to become even stronger is to go back and study the fundamentals once more.
No matter how good you are or how good you think you are, it is important to go back and revisit the basics. Yet it is tempting to say "I know that" or to gloss over the basics of a craft that we think we are good at, yet this is a grave mistake, as we like to say in Hapkido: "To consider yourself as knowledgeable is to commit an error." Once I get to the point where I believe myself as knowledgeable, I know something has gone horribly wrong, since I should be realizing how much more there is to learn--not praising myself for how much I think I know.
Occultism has a lot of the characteristics of a martial art. It has a nearly infinite progression, and many of the techniques simply cannot be mastered without repetition and practice. Some of the techniques can cause real harm to the practitioner, the client, or someone else and some are extremely difficult to learn. It is important to build those basic foundations before continuing, to quote Diana Paxson in Trance-Portation:
Even, or especially, if you already have a given skill, you must practice it regularly--several times a week--for about a month, or until you feel ready to go on. Those with more experience may actually find some of the early lessons harder, as they may have old habits to unlearn. However, you will find that these skills, once mastered, are useful in themselves and may provide a foundation that can support the practice of more esoteric skills like oracular and possessory work.
Yet many times people like to treat occultism as if it had no learning curve. As if one can simply spend a few minutes, read a book or two, and suddenly be an expert. Many others--some of whom actually are quite talented--have let their success go to their heads in whatever role they fill. As a result, they gloss over the basics in their own practice, having lost sight of their importance. As a result, they stop advancing and stop improving.
Breaking it Down
Having established that basics are important, what are the basics? Many of these vary by tradition, I think for most occultist practices the following makes a good starting point:
Meditation, prayer, and/or devotional work.
Grounding, Centering, Shielding
We can probably expand from there, but I throw those three categories of practice into "things you can't go wrong with," that anyone can learn and most people could benefit from knowing.
Mindfulness, as discussed previously helps us with the art of living consciously, of making each day count. The exact mechanism we use for the practice (I like mindfulness through breathing, but each individual may have different things that work better for them) can vary, but the essence of it remains the same: practice paying attention to something, practice seeing the world without preconceptions.
Meditation and prayer have a host of benefits for self-reflection and training the mind, along with getting us closer to the gods.
Just about every introductory book on some form of Occultism starts with Grounding, Centering, and Shielding in some form or another. Pathwalker's Guide starts out with a few basics in this area, Trance-Portation does as well. My Celtic Trad teachers repeatedly drilled into me "practice grounding, practice centering, practice shielding. If you do nothing else, practice those three." Everything else derives from them in some way, and they are the techniques that are most useful in our day-to-day lives.
Walking into a stressful meeting? Ground, Center, Shield.
Feeling overwhelmed at work? Ground, Center, Shield.
Roommate's depression rubbing off on you? Ground, Center, Shield.
Feeling anxious about tomorrow? Ground, Center, Shield.
It isn't a panacea by any means, but it is a good first step and it can't hurt. It is also fundamental to future practice, from thaumaturgy to theurgic magic, from journeying to blood walking, from Kabbalah to Shamanism, they all include some variation of grounding, centering, and shielding.
In terms of good examples of how training the basics can work, Trance-Portation does a great job of breaking down journeying into it's fundamental basics which can be practiced again and again. I hope to see more books like it in the future.