be careful elongating things Elsa, it's against site rules [though i'm not sure how it works for numbers]
it's hard to make a believer out of a skeptic, or one who won't cast spells. belief is part of a successful spell. casting spells for fun, for practice, to show of, or to prove it works isn't a good idea. it's powerful, magick rewards those who deserve it and punishes those who do not. meditation, charging, grounding, centering, and shielding with energy as well as making psi balls, so you and your friend can feel the energy around us can help her start to believe. at the very least it's a good skill for you to master if you're hoping to cast spells.
there are many reasons why a spell might not work for you. i've mentioned this to you before, if you're expecting ice powers like in Frozen, that's fictitious, and spiritual magick in the real world does not and cannot grant such abilities. a general guide to help is place spells into two categories, energy/forces and physical change/elemental control. magick is energy, a spell is cast with this energy to create subtle changes in our life to bring desired outcomes. spells dealing with energy/forces such as love, luck, or healing are generally possible because you are channeling this energy to change the current energy surrounding your love, luck or health. spells to control/make ice, grow wings, or turn into another being aren't possible because although magick is powerful, it's a force of nature, it cannot go against nature, and as humans it is not in our nature to do those things. it can get tricky, but it gets easier with practice and study. right now, stick to study and getting 'the basics' down before casting spells. even if you get a powerful working spell, if you don't focus or send forth enough energy, it will not work.
i don't know your path, so i can't help you too much more [such as books and articles] specifics will help greatly. blessed be.