First, it's important to make sure that your mundane life is in good shape. Occultism is not a refuge for people who can't hack ordinary existence! If your bills aren't getting paid, you're neglecting your health, and so on, those are warning signs. Deal with them, using ordinary mundane methods, before busying yourself with magic. Adequate nutrition, enough sleep, and all the other basic rules apply.

Second, a background in occult philosophy is very helpful, since it gives the student a mental framework to go by. That helps avoid confusion and disorientation.

Finally, regular meditation is essential. The lack of meditation practice is one of the main sources of mental imbalance in magic. Mind you, it can be overdone, but 15-30 minutes of meditation a day, every day, never hurt anyone and helps maintain mental clarity.