Brushwork is a very personal part of the artist. In some way, it defines artist's work and style. To paraphrase what Mr. Zbukvic said in one of his lessons. "If there's anything that sets one artist apart from another, it's the calligraphy. It cannot be taught, and shouldn't be taught." And I agree completely. An artist's brushwork is an extension of his intuition, his/her natural response to the form and shape with his/her hand. However, I think this is still worth talking about because one of the biggest things my students struggling with is brushwork. These are some of the most common issues I discovered. I want to share them with you and also talk about how to remedy these issues:

Dabbing - This is by far the worst but common habit students have. I suspect it's due to lack of confidence and fear of making mistakes. When your keeps going back to the same area with your brush over and over, you are pushing the paint around and not allowing them to do their work for you. Make a decisive stroke and leave it. You can go back and fix the shape if you are not happy with it, but you have maybe 10 seconds to do that, and you are likely to do that only once. If you are really unhappy with it, sometimes it's better to press it with a dry paper towel to get the paint out (if it's wet enough).
Too fast - This is something many gets wrong. Lose painting is not by painting super fast. Yes, speed is important, because watercolor will dry up. But some people overcompensate by painting too fast. So fast and they stop thinking. A fast loose stroke is not done without any thought. If you see me painting, you can often see I slow down while leaving my brush on the paper. That was me trying to think about the shape I am making, where will the brushstroke ends.
Repetitive strokes - When you don't slow down and think, you are just trying to fill the space with repetitive marks. And if a painting is filled with repetitive shapes and marks, it shows the artist is lack of experience and wasn't thinking when painting. This is why some of the master's painting are looking so alive. If something as identical as a flock of birds, the master is still able to paint them out in a non-repetitive, lively way.
Strokes have same thickness - Besides some student's brush strokes being repetitive, many times they also have the same thickness. A brush is a flexible painting tool. When painting shapes, remember to vary your pressure. Press down harder if you want to make a stronger, bolder mark. Lift your brush slightly and lightly touches the paper if you want to make lighter, delicate mark. Think of your self as a conductor, the music can be light and brisk or heavy and impactful depend on your movement. The same goes for painting. You have control over how your brush strokes look, think about it as you paint.

I personally believe brushwork is something more in the advanced category. You should have a solid understanding of fundamental and how washes work before you start to work on this. Therefore, do not stress yourself too much over this if you just started to learn. Believable perspective and lighting are still more important than having good brushwork. But when the time comes for you to advance and start to give your painting a more personal voice, remember these tips.