Ethics essentially comes from empathy and civility, which means one, must respect others, their lives, and beliefs. To do this, one must not indulge in casting spells intended to harm, control, and manipulate other people. As a responsible Spell-Caster, you must treat everyone with respect, even if the supposed act is fictional. One must also be heavy on their respect for traditions, as every course draws from specific cultural traditions, so it is a responsible behavior to approach them with respect and avoid appropriation, at all costs. You can also research and learn from reputable libraries dense on spell-casting rituals.
One should always cast Spells for healing, protection, or positive purposes. These are great places to start and be
And the last and most important is to always keep a positive intent. You must focus on using your newfound knowledge of casting spells for the greater good.