This is the best advice one can give and follow. There is no better way of learning, of course if you actually want to apply your knowledge in the real life.
You want to become a blogger? Start a blog, start writing and perfect your writing on the way, while writing. Reading about writing, doing a creative writing course, they all might help but in the end only the doing will make you a good blogger. It will take time, but it will happen and you will have a laugh when you return to your first posts and realize how much you evolved from that moment. Not to mention that it would be a good performance indicator for your skills.
You want to become a web developer? Start coding, learn how to do it while you are doing it. The result will be tangible and you can use it as a business card, to present your skills.
You want to become an expert in customer relationship management? Start with your environment, observe the needs of those around you and find ways to better satisfy them (starting from your loved ones to friends and collaborators). Treat everyone as a customer, a customer of your affection, of your friendship, of your loyalty. In time, it will come naturally to you to understand customers’ needs and respond to them.
You want to learn about art? Start by doing art. Buy a paintbrush and start doodling.Yes, you can benefit from classes and learn techniques from the many sources available to you but the only way to become an artist is to create, and that’s what you should be doing.
… and the list can continue. I am not entirely eliminating schools, trainings, online courses, advice from experts and any other source of information and learning, use all resources you can find around you to be better at what you want to do. If you want to excel though, you need to just do and persevere in that.
That’s all there is to it: do it! Whatever it is, start now!
*Photo credit to Startup Vitamins (http://startupquotes.startupvitamins.com/post/41941517470/the-best-way-to-complain-is-to-make-things-james)