I have had started my Julia journey months back and have been working to improve my skills to an advance level. I am a research student and my work lies in areas of computational electromagnetics, signal processing and imaging.
I would be glad to find inputs to improve my skills in Julia as it would help me better in my work as well.
I think a very good way of improving programming skills is to contribute to open source projects. Choose a package that you use and start contributing to it. You will very likely learn a lot and get feedback and advice from top programmers. Edit: For electromagnetics you probably use differential equations? I think the SciML ecosystem is an excellent place to contribute, they have a live chat where you will can discuss with the experts 24/7.