What should I do after drawing spells?
After playing a bit longer I can answer this anecdotally.
The swirling circles that you see after the spell has been cast is an indication of the spell is going to success or fail.
From what it look like, it will turn more red if the spell is failing and then when you succeed, it turns blue/white/purple colors.
As per our comment discussion, this is similar to the animation in Pokemon Go where the ball jiggles and wiggles until it shows you've caught it or not, just prettier!
Again, this is all anecdotal evidence, be nice if there were some hard references to associate.