You’re a designer
Every one of us goes through motions of life and leaves traces of activity. Other people see, touch or interact with those artifacts. Their experience of that depends on you because you’re a designer. It can be good or bad but it must be. There is something every one of us leaves along with the artifact itself. It can be an additional bit of care, attention, and precision or ignorance and roughness.
The first step of becoming competent is to understand its existence. In essence, a design is a language of things. If it’s a language, it can be learned. A decision not to do so is equal to a decision not to learn how to speak and write.
If your artifacts are non-functional, ugly or hard to comprehend you’re a bad designer. You can’t avoid being one. Therefore, you must become a better one.
I would recommend starting with typography. It’s omnipresent and useful. I find this short yet valuable guide a good introduction.