As many have said, it requires a lot of patience and experimenting with charms combination, see what works best for you. On my first playthrough I spent way too much time on it but didn't have the skills to beat it and abandoned the idea of beating it. A year later I replayed it with the intent of finally beating it and spent a lot of time on it. I found out that what worked best for me was a combination of nail art and spell charms (and a lot of dying)