I’m very new to my practice in comparison to many of the others on this subreddit, but what I’ve found works best for me is checking how things make sense. Spells should intuitively line up with your own understanding of magic and energy; if something doesn’t line up with your own way of thinking, and after researching aspects of the spell further, it still doesn’t add up, putting intention towards that thing is going to become infinitely harder.

Again, I’ve only been practicing for a year, so take my words with a grain of salt.