To be a painter is to be yourself. A painter, who only begins his journey in watercolor, should remember that the most valuable thing he has is himself with his desire to express himself. There is no doubt that everybody makes mistakes or fails, but the important thing is how to treat your failures.

It is hard to even imagine a painter who has abandoned everything because of external factors, such as advice from outside, condemnation or denial. The motivation to act is not on the outside, but on the inside. You can't just turn off your desire to express yourself, there are no such buttons, creativity is a need of the highest order.

All you need to do is accept the fact that you can create a painting that you wouldn't be happy with and that's absolutely fine. You should treat your failures as additional motivation to improve, to extend your knowledge and try once again. At the end of the day - it is just a piece of paper. Remember, the point of growth of each of us lies outside the comfort zone. If you think that the method of constantly creating perfect paintings is a way to grow as a painter, then you are very mistaken. 

Sometimes, to make a qualitative leap, you need to strongly reformat your thinking, while trying to hold on to principles and past experience, will be an anchor pulling you to the bottom.

General advice is: in case of a failure, do not lock yourself in, do not think that you are not capable and stop claiming that you are not good enough for this. Do not perceive material goods as an assessment of your work, it is the need to create, the energy, that feeds you and makes you create beautiful paintings.