Not every artist designs the same way with a particular brush. This is a myth and the talent is the artist himself/herself and the brush has got nothing to do with it. The artist is the creator of a beautiful artwork. When you are a beginner, focus on the basics rather than thinking about the brushes. Digital illustration is more than brushes. You can always choose any default brush from the brush panel and make good use of it to illustrative your creativity. It is a misconception that brushes do everything to bring out a good piece of art.
It is important to save your work in a properly layered format and while sharing do it in a compressed format. This not only saves space but also helps protect the original work. You should know the compatible file types while saving and sharing. With regular practice, digital illustration is the easiest and enjoyable job. When you are ready for a career in digital illustration, start presenting your work in a safe portfolio with best art works you have created. It will not only increases your chances of getting that good job but will also earn some criticism for better knowledge and improvement. Every art piece is an experience and an exposure to learning something new.