Whenever the topic of flourishing comes up, I always add a link to John Steven's IG because his flourishing is dreamy.
https://www.instagram.com/calligraphile/?hl=enMy suggestion for adding flourishing to italics is to learn the basic capital letters first.
You'll notice on John's looser variations of italics, he doesn't stray too far from the basics.
There is still a lot of symmetry to loose italics.
Before you add full flourishes, learn how to add just a swash to each capital letter.
Notice that both swashes and flourishing will have basic shapes.
Sometimes they are more elongated - other times they are rounder.
It's pretty tricky to mix the two until you have mastered both.
If possible, try to learn a couple basic flourishes and then gradually add a few more - one at a time.
Flourishing is often compared to ballet - start with basics - and plan on putting in a lot of time if you want them to look professional.
Successful flourishing is often done quickly with your hand not quite touching the paper - using whole arm movement.
Most teachers will show students how to do a couple practice *swoops* in the air - just above the paper - and then do the actual flourish on the paper.
It's a way to help you relax so you don't choke.
When I was first learning the figure-8 flourish used on the tails of y and g -
I would leave the ascenders off the h k l - and then turn the paper around and add the figure-8 strokes.
Eventually, I could make the flourishes in both directions - but it was a helpful trick til I got there.