I would like to improve my design skills. My main focus is web development and even though my coding skills need to be improved upon a lot, right now, design is where I feel like I lack the most.
I do have quite thorough knowledge of photoshop, I learned most of it during retouching my photos or when I occasionally create some random website mockups. But it is really missing that professional touch that I would like it to have. I think that what I'm missing is the good practice in design, the rules and basically how are things done properly.
So what are some good books or courses to improve this?