Negative painting can only go so far as other things in watercolor need attention. Shapes and shadows are very important for both realistic and more abstract things if you want to make them somewhat recognizable! Consequently, I have been painting fruit and vegetables all morning, to the point I am feeling crazy. Some subjects are more successful, others not, but the lesson is to paint shapes directly and with some finesse, as well as to create shadows while the subject is either dry or wet. Click through at your convenience for a trip to the market.
One thing I have realized from painting all these things is that patience, once more, and mindfulness, is necessary to get anywhere with these things! What looks spontaneous often is not. Instead, it is made up of experience and thought and so on. Persistence is my only hope . . .