I'm not going to straight up tell you that not EVERYTHING is possible with magic, but if the instructions are outrageous like"if you're swimming imagine yourself as a fish and you'll become a mermaid"(which there is a bunch of) you still need to think rationally about what is possible. Note that if you relieve in magic these seem to contradict, but there is a second standard between legitimate and "fluffy" content. If you don't see it work, dont think about it. It takes some practice ad if its something like to get money then it may happen in let's say a month, and at that point you forget. About tips, (from memory) there are many variables that affect how you plan to go about casting. These include the time of day, year, season, location, energy, and moon phase.
(From the site)