Basically a designer encounters soft skills and hard skills. It’s a lifelong process - I’m at 22 years and still learning from everyone. There are some personality traits that seem to be important to being a good designer - but I don’t have time or energy to go through that list. Seriously Diva’s out there - I see you.

So you wanna take some classes. You know, things that are accountable to someone besides play nice and don’t take things personally. OK, here’s an attempt.

1. Learn HTML & CSS. If you don’t understand how web pages work and how they are built, you can’t possibly hope to design them. Try Code Academy online, but there are also good books out there.
2. Learn Photoshop. There are plenty of design applications out there, but if you only ever learn one, learn this one. The reason: once you can use Photoshop, you can use any of them. The bonus reason: employers will search for this skill in your resume, and if they don’t see that you know Photoshop, they might not even consider you regardless of what you do know. All the photoshop books and tutorials have their benefits, but feel free to check out Photoshop for Dummies – pick the edition that matches whatever version of Photoshop you can get your hands on.
3. Learn basic typography. There are a lot of great articles for this Design Festival, Smashing Magazine, PSD Tuts and 24 Ways, There are a lot of great books out there for typography too – start with The Elements of Typographic Style and move on to whatever holds your interest from there.
4. Learn basic color theory. Unless you intend to be designing in black and white forever, you’ll need to understand when and why to use color. Check out these articles: Color Theory For Web Designers, Basic Color Theory. Ignore anything you see about what colors mean because they will differ for each culture and demographic. Red means one thing to the Chinese, another entirely to Americans. It means one thing to older Americans and another to teenaged Americans. So just forget all that temporarily. Read The Principals of Beautiful Web Design.
5. Learn about layout. This is something you’re probably going to get instinctively, or never really get at all. Start by researching Responsive Web Design and follow it wherever you want. As long as you start understanding layouts from the responsive web design standpoint, you’ll be fine.
6. Get a feeling for producing UX deliverables. At the very minimum, every UI designer needs to know how to make good wireframes, low-fidelity mockups and high-fidelity mockups. Depending on where you go to work, you might also have to write styleguides or work from them, write specs or PRDs, or build prototypes. Don’t just follow my links – google all these terms and read everything you can. Develop your own style - It’s awesome, actually.
7. Learn about usability evaluation methods. Even if you work in an organization where someone else does the research, you need to understand methodologies, when to use which one, and how to understand whether you’re making good designs. It’s good to do customer requirement gathering before you start your design, and then evaluate your design afterwards – even if you’re just using budget, quick or halfhearted methods. You can’t design in a vacuum unless you’re designing something only you will use. Read Don’t Make Me Think and Website Usability: A Designer’s Guide and then keep reading other books that those books recommend.
8. Learn the best practices for web design. Again there are hundreds of good resources, but my favorites are Smashing Magazine, Jakob Nielsen (even though he’s controversial), Bruce Tognazinni, and Designmodo. Subscribe to blogs and read them every single day. Best practices evolve, so you need to keep up with the latest research. Understand the difference between designing web sites, web applications, mobile applications, desktop applications and experiences. This could be a whole blog post of its own, so my recommendation to you is to google all of the aboves. You can get information overload.

This is just your basic “get an internship” level of learning. At the University level look for an HCI or CHI or UCD program. (In my day it was Human Factors Engineering - HA) Some great designers have come from architecture, psychology, art and computer science. One road doesn't exist but there are some must haves. I hope this list helps you out.