k, i'll go with a really old one, the abracadabra spell. on a piece of paper you write abracadabra, taking away one letter each time, until all the letters is gone and it forma a triangle. this is an old way of combating the common cold. personally i've never tried it, but it's claimed to work weaken a cold. how this works is you transfer your energy into the words, visualize yourself [or friend] getting better. all spells work the same, how well you can focus and charge an object will increase it's ability to work.
you do have a point though, it is hard to believe writing something on paper would do anything, but it can. a spell is nothing more and charging an object to help you achieve a goal. a spell could be simple like washing your floors while saying a protection chant, or as complex as casting the same spell for a month straight. whatever feels right to you is the best spell to do. personally, i study potions for that reason, and am trying to learn more about herbs, but i have trouble remembering them all lol.