Spell work is essentially just amplified manifestation. It uses the law of attraction. If you are unfamiliar with the law of attraction, it is a VERY popular thing implemented by many wealthy, famous, successful people and is talked about by thousands over YouTube and on podcasts by those such as Abraham Hicks. To simplify it, it goes off of the principle that you must be on the level of all that you want to attract. If you want good in life, lots of money, healthy and loving relationships- you must be good. Have good and confident ideas of money, be a loving and kind person- but out of good nature. This is why it is so important for us to heal in order to come from a place of pure desire to do good. Then we must expect to receive what we desire. Ask for it, work towards it, and know you will receive it, because there is no reason as to why you will not.
Spell work is essentially a ritual which sends your intent into the universe. Where some use law of attraction and simply ask/manifest, spell work is a more powerful way of declaring your intent and manifesting. It is a kind of finalised, more practical and powerful way of manifesting.
Spell work is great for getting in to a certain vibration, it is great for hacking the system and getting what you want. It is a powerful and useful tool.
If you are expecting spell work to fix your problems effortlessly- you are in for a shock.
Spell work is not to be feared however it is to be studied and read up on. You need to know exactly what it is you want and be willing to get there by any means possible. If you want love but you have blockages surrounding receiving love (in your heart chakra or programmed behaviour), a love spell will work, however it may be painful because it will send you whatever love relationship you will need to serve your highest and greatest good. You will likely attract a karmic, or a twin flame. You have attracted valuable love, however it may not be this complete sunshine and rainbows thing you were aiming for if it was not meant to be.
Spell work requires work and is not just a short cut.
I used to do spell work every week for what I wanted, and I got all the blessings I asked for, but it took me 6 months away from spell work, working through all my problems, clearing and reprogramming my mindset, learning a bunch of stuff. All setbacks were blessings in disguise. I am very glad I did the spell work, but was unprepared for what was to come and what I was to learn.
Once you have learned, spell work will become less necessary in your life. When you feel a desire or a calling to do it, do it, because it is guidance and it is taking matters into your own hands. Utilise this powerful tool, but be mindful.
As for spells regarding inflicting harm on others, our of revenge, fear, banishment- it will all end in tears. What you send out you get back three fold, that is the Wiccan teaching which never fails to live up to its truth. Focus on protecting yourself, maybe even doing a return to sender spell to protect yourself and those you care about. Do not inflict harm or manipulation. Karma takes care of all and you have no business messing up your own karma because of lack of faith in the universe.
The universe works in mysterious ways, so when working with it, expect surprises, detours and lessons. You are safe to have faith that all will end as you intended, perhaps even better, but the journey there may be long and bumpy.