A while ago I found Lori Rase Hall's video painting demo, where she shared her technique for making gorgeous water-colours. It really inspired me back then and I made a few that I felt made the grade, and a few that were flops :) If you like speed painting, have a look here and here. It's magic to watch.
Once the main colour goes on (after patiently waiting for each section to dry) the design is embellished with patterns & lines and with a deeper colour & consistency of paint, or using pens. Last easter weekend I re-visited the technique and spent the whole day practicing. This was the best result and I'm looking forward to doing some more. Practice, practice, practice!