Be honest with how you learn best. If you shine in a formal setting, invest in a course, but if the classroom bores you silly don’t. Once you’ve found what works for you, stick to it and learn in a way that suits you not in a way that you think you ought to.
Having an experienced designer to discuss ideas and techniques with is worth its weight in a host of precious metals. Not only can a mentor give you great career advice, but having someone you admire take an interest in your work is likely to make you push yourself harder than you would going it alone.
Don’t shy away from working with others, especially designers that are out of your league. It may be nice to be top of the pile, but seeing the best in action can have a phenomenal effect on your skills, especially if you use your ears and eyes more than your mouth during the project.
If you’re guilty of clutching to your security blanket of tools, it’s time to cut yourself off. Next time you open Photoshop stay away from what you know and try to get the same results you’re after from the dusty palette of tools you’ve long been neglecting. You might find something you really like.
Time certainly is money and while taking a few hours to tackle an online tutorial might seem inefficient, especially if the client work is piling up, remember that in the design game your skills are your worth. Investing in yourself is never a waste of time or money.