This one's from yesterday:
I made a bunch of new brushes out of some marks I did with watercolors. The file doesn't want to get attached but if anyone wants the .tpl file (works from cs3 upwards), just ask.
I realized that using good-looking brushes helps with speed and vibrancy of colors because the big brushstrokes you lay at the start don't have to be blended afterwards. On the waterfall picture, probably most of the area of the rock wall is covered with strokes I did on the first half an hour. I made sure not to tinker with them to keep the vibrant colors of the initial sketch, just added shadows and details.
All of the environments took me about 4 hours. I think the main thing that sped things up was focusing more on painting things from background to foreground as opposed to painting them in whatever order I feel like and trying to keep the layers organized. With the time limit I set for myself, I also had to get details painted at once rather than leaving them on hold while I work on something else.