Product illustration practice

I tweeted recently that I'm looking for a course to give me some structured teaching on illustration as it's a real weak point for me, and something I want to get better at.

I'm specifically looking to improve my product illustration skills: taking a concept or feature from our app and showcasing it through stylised product imagery. If anyone has a course they can recommend to help me learn to conceptualise and compose product illustrations please drop a link in the comments!

So far it seems that nothing like that exists so I'm just playing around and trying things to hone this skill. Here's my attempt from today. See some WIP in the attachment, the image on the left is what's currently live on our site and the heading this is next to is "Grow your audience to grow your income". With this image I was trying to illustrate how your audience will grow when you offer opt-ins through ConvertKit forms.

Feedback welcome! Help me learn :)