Hi welcome to Core.
I've was a furniture maker in a previous life, wood and metal work requires so much investment into the craftsmanship that it's easy to produce poor designs. I felt like 10% design 90% make/build about summed it up. - why I shifted to ID.
It's unfourtunatly not as simple as picking up a few tips and tricks to become a better designer, but there's a number of books to get you started, IDSA also has a list. Check into Arts and Crafts schools who offer non-matriculating courses (not many on Core use or know about them) I know of several excellent ones here in the States but not EU, sorry.