One way to increase your concentration and speed up your understanding of watercolor is to paint, in one sitting, from a fully saturated sheet of paper that, as it dries, produces increasingly harder edges.
Step one is to look carefully at your subject and think about the categories of edges, from most soft to most sharp. The more levels of soft to hard, the more interest and contrast will evolve, giving your painting more dimension than if you have only two or three levels of soft to hard edges. This kind of exercise, thinking about edges apart from subject matter and even color, will sharpen your artistic eye. It can be a struggle to see things in new ways, but once you do it a few times it will become a natural process. Along with your good observation skills of line, color and values, you will become more of a multi task painter, stopping less often to switch your thinking from one aspect to the other.
In addition, if you attempt this way of painting, you will have to plan more, something so many new watercolorists have trouble with. They hope to work things out as they go, and this usually ends up with a lot of errors. Once you are proficient, and quick in your decision-making, you will be able to make more decisions later, as you are working. But in the beginning, extensive analyzing  of the subject, with those four ideas in mind (color, edges, values and line) will result it fresher, more spontaneous work than if you are stuck with a lot of repair work.
Also, painting in a very concentrated manner will help release your deeper levels of perception of what is going on with your materials. You are focusing on the drying paper, working with it to add and subtract water and paint, but in a more dynamic relationship than if you approach your painting in a wet a section, wait for it to dry, take a coffee break, then do another section. Taking your concentration away from the painting causes less awareness of the process.
It can be exciting working with “active” paper. Along with the water in the air, the water on the paper is alive and responding the actions of the painter. It feels more cooperative, and you begin to understand the nature of the paper in a new way.
To do this, soak a piece of 140 to 300 pound paper (remember, the thicker the paper, the more action) and place on a non-porous surface like Plexiglas. Have all your paints ready to be active as well, no hard lumps of paint allowed in this scenario! Fresh, or freshly active paint the consistency of toothpaste, and in large enough quantities (about a tablespoon each) to avoid breaks to fix the paint, will make the process go smoothly. You want to have nothing to worry about except the translation of your analyzing and the use of the materials. The more pre thinking you do to decide what you are about to do, the quicker the process goes: you can literally paint a great painting in one hour, with a fresher look than one you might slave over week after week.

 
1. Learn how to make brown
2. Learn how to paint water (or faces or trees or anything)
3. Complete a painting in a set amount of time
4. Paint like Monet (or whoever)
5. Paint loosely and with emotion
6. Impress my friends with my talent
7. Make money by selling paintings
8. Win contests or become famous
 
This is the wrong checklist for becoming a good painter. These ideas all keep you from progressing and becoming adept at the medium. It is what most people come in with as a checklist, even if not completely consciously, because of the misconceptions in the general public about what art is and what it is for. There is a lack of understanding about art because of so little education people receive, at least in most of the US culture, and because the current culture keeps reinforcing the wrong concepts.
While it is true that there are basic things to learn, this is not the way to phrase them. The real job of becoming at artist is improving our ability to observe the world in greater detail and with greater understanding.  Otherwise why to we keep accepting an endless series of paintings of the same things over and over: portraits, landscapes, and still lives of fruit? Hasn’t it all been done before? NO. It has not been done by this particular individual before, and the key is the fact that no one on earth before or since will ever see a sunset (which also changes) or sunflower the same way ever again. We have to capture that as a painter, and help the world to see things in a new way, a way they have never seen it before.
SO the process is about breaking down the external world into painter’s terms and learning to discern these things around us: the exact color of a leaf and how it changes from one color to another across its surface, or the intensity of contrast between a cloud and a nearby mountain range.  Then, after learning the mechanics of the materials, the endless journey of capturing these visuals begins.
Here is a better checklist for a new painter:

1. Notice how many different colors of brown occur in one room: or even one surface like a table.
2. Try to find as many different colors and shapes in a body of water that you can, then notice in masterpieces how other artists depict it.
3. Figure out all the things that need to happen to make a painting and make a realistic assessment of the time involved, allowing as much time as possible for each stage since the goal is not efficiency but complexity and beauty.
4. Study not only Monet’s methods, but the lives of artists to see what they concentrate on.
5. Impress fellow artist with your hard work and achievement. Your non-painting friends will be impressed with your most elementary efforts since they can’t do it at all. And they might not even like you for it.
6. Learn to paint accurately and with exquisite detail: the looseness comes with practice.
7. Make money doing something else to pay for the time to paint. 90 percent of accomplished artists do not make enough money to live on even barely.
8. Fame and glory is not what it seems. Those who get it often lose the joy of painting, being in the public eye and plagued by expectations. Seek the glory of making art only.
   

A former student remembered that I say to use all six basic colors in each and every section of a painting: that is, every section bound by a hard edge. She successfully did this but was dissatisfied with the overly colorful look, verging on psychedelic.
So she is ready for the next step: the fine-tuning of how MUCH of each color to use and how much to blend. Just using the same amount of each color in each section makes for a colorful patchwork, and over mixing of the colors makes mud. So the key is the ultimate skill needed by watercolorists: being able to determine how much water is in three areas: the brush, in the paint, and on the paper, and how much pigment is on the brush.
Of course experience makes this happen, but first you must mentally pay attention to each part of this. Do you know how wet the paper is? That will determine how far the paint spreads. Are you conscious of how much water is on your brush? Best to keep a semi damp brush but not bring extra water to spread the color before you want to. And sometimes you think you are grabbing a glob of “dry” or paint with no water added, but instead a little water gets in there and you have closer to a wash.
This student was already great at seeing all the colors I asked her to include: she saw variations in an orange petal that added up to hundreds of colors so is past the idea of painting the petal a general orange, resulting in flat, boring paintings. But she was not making a judgment as to how much and exactly where the orange was duller, lighter, darker, or actually redder than orange, or more yellow than orange. She could even see green and purple in a generally orange section.
Now she will try to use smaller amounts of all the colors, so as to not put too much. You can always add more. And she will be more careful as to where she places the alternate colors. This is the hard work of seeing the world as it really is, not what it looked like at first glance.
Don’t forget, too, the three uses of the brush: delivery of water and pigment, then mixing with a clean brush, and later removing with a clean dryish brush (lifting), if needed.
This next step to excellence is hard like all steps to improvement because you might feel you have come so far already, that you don’t want to hear about yet more ways to get better. So if you feel that way, rest on your laurels until you become dissatisfied with your work and want to improve. After the above lesson, there are many many more ways to get better. You can stop at any time and just paint the way you can, enjoying it but not needed to improve. That might become boring  and then you can go back to more advanced lessons.