All the spells under the category of Fantasy Spells won't work. Also, weather spells(for example, creating a tornado spell), resurrection spells, and any other spell that seem unrealistic and pretty much impossible, will not work, because they are what they are, fake. It's not the spell that was made wrong or so, it is simply impossible. You cannot break the Laws of Science in anyway.
Spells under the category Spiritual Spells are likely to work. Still, it is important to discern(to distinct what is real and unreal, fake or true). Protection Spells, Banish Spells and Binding Spells will work if you do them correctly. Love Spells and Luck Spells will work unless it isn't unrealistic. For example, you can't change someone's sexual orientation with a Love Spell, and with a Luck Spell you won't win the lottery.
Trick Spells won't work. Flying Spells, Illusion Spells, Invisibility Spell, Teleportation Spells, etc won't work. They are only possible in the comic worlds, which aren't reals, or if you can Astral Project, then you can pretty much do or be what you want.
Beauty Spells won't work. You cannot change your physical body, unless, of course, if you are in the Astral Plane.
In conclusion, stay away from categories such as: Trick Spells, Beauty Spells and Fantasy Spells. Also, this does't mean that in the other categories spells will work. I would say 95% of the spells in the site won't work, so people usually concentrate in meditation and their spirituality, such as bonding with their deities, the God and the Goddess, or any other entity.
Besides, creating your own spells is better! This site offers great knowledge in Herbs and other magical things that will help you in your spell creations.