Problems with hitting skillshots

I'm a Gold 3 support main, been playing this game for around a year now with a 2-month break late last year. I really struggle with hitting skillshots on any champion.

I've been mostly playing champions that don't rely that much on skillshots. I main Milio, Nami and Rell. Recently I've been trying to learn a mage support to add to my roster and it's been... tough. I miss skillshots even when people don't try to dodge them. It's really embarrassing to miss basic stuff like Lux Q, Zyra E and so on.

Is there any way to practice my skillshots other than just playing normals? I'd like to focus on it more to learn faster.