These are rather simple step-by-step guides for how to draw flowing water, reflections and rain by digital means. I myself used Photoshop CS4 when making these, but the tutorials aren't really bound to any specific program as the only tools used are the regular, round paint brush and smudge brush and a couple of layers. Most digital art programs will have these or similar functions available, so as long as you have something more advanced than MS Paint installed, you'll be set.
Always work in a much larger scale than the pinished image, taht's a basic rule for digital art. All of these pieces were about four times bigger while I was painting them, and looked like total blaah in full size. Minimizing makes everything look great.
Flowing Water
When drawing a current of water flowing through a rocky area, a very common setting, the largest obstacle in the beginning is making the mater flow naturally over and around the rocks. To overcome this, I recommend starting by drawing the current itself (with a light color, as constantly moving, foaming water is always mostly light by color) and then carefully placing the rocks into the river afterwards.
Then it's time for some serious error-fixing time to make the flow of water around the rocks natural. I had a really veird valley-thingie in between the two waterfalls to the left, and obviously that would be the path water would be flowing through if this place existed in nature. So I've slightly redesigned the flow of the river.
Each little trickle of water into the pond creates its own ripple on the surface, yet when they flow together the stronger ripples usually trump and negate the less significant ones. It is a good thing to keep the white ripples on a separate layer above the rest of the water to allow easier editing of the water later. Something I forgot to do here, uggh...
The foam in the waterfalls makes the flow of water look heavier, while no rampantly flying foam will give the current a far calmer feel. Your choise.
When dealing with moving water, reflections are a big no-no, as you need a completely peaceful surface for that. But shadows are a nice substitute, either showing different depths in the pond or simply the shadows of adjacent elements. This is where we really want the ripples to be on a separate layer, I had to do a ton of unecessary work here because I neglected to take care of that. Or you coul do this all in the opposite direction, as one would do with traditional paintings: paint the white parts on top last.
Rain
When painting a rainy scene, the best place to start is with a foggy background. The heavier the rain, the hazier the scene.
Before actually drawing the rain itself, it's best to finish up the actual background. Strive to achieve a vertical movement in the lines, and the perfect tool to use for this is: the smudge brush! Keep the strokes subtle with softer rain, and more pronounced if you want a real "all the angels are crying"-thing going on.
Now, the rain itself. Make sure to create a new layer here, or you'll hate yourself if you notice mistakes later on. To achieve this effect, pick a round, large brush, set the opacity to around 20% or less (whaterver works for you) and a light color. Try not to pick pure white, it will create a dull, grey feel on dark areas. Here' I've used a very light turquoise color. With that brush, start drawing vertial lines like crazy! Don't think or plan things, rain is irregular an random by nature so just let it flow. Let the strokes overlap and create thicker lines here and there, and a slight crookedness doesn't hurt. You can also change the size and opacity of your brush now and then, and why not do the same thing with the eraser if you feel some areas are becoming too cluttered.
Again, new layer. Now we're adding a few more defined, more visible streaks of rain on top of our "background"-rain. You'll need a small brush, light color, about 40-60% opacity and a steady hand. If getting the lines straight turns out to be a completely impossible task, some kind of line tool should work fine here too. It might leave a slightly too mechanic feel, but othervise is completely fine. Just make sure to slightly vary the line thickness, opacity and direction.
Finally we add some pretty little droplets of water falling from things, and a very slight splatter on top of any objects. Again, don't use white, except to finish off some absolute highlights here and there.
Reflections
The lazies way to create a reflection effect is simply copying your object, flipping it vertically and baboom!: awsome, perfect reflection! Of course that is both very obviously lazy and mechanic-looking and kind of difficult to do with several objects in the picture. They all need their own reflections at different levels, some times overlapping each other.
Start by sketching out the raflections of each object to check the overall composition of the image before starting the actual painting process. They are, after all, a very significant element in the scene, and could drastically change the layout of an image. After making sure that the composition still looks fine, finish drawing everything but the water. You can't really start any reflections before the thing that's being reflected is all done.
Now, finally, the reflections. I bashed the "copy-paste-flip" method at the beginning of this tutorial, but it is actually a very useful trick to get the reflection right for complex objects. After you've done the flip, create a new layer and draw the key elements of the fipped image on it. Then simply delete the flipped object and finish the reflection as if you never did that dirty little trick. Because all it was supposed to be was a guideline to get the reflection just right. This trick is probably completely unecessary with simpler and or smaller objects, such as the little swan...lings and the island in the background.
It's a good idea to make the raflections fade a bit toards the bottom (use a very soft eraser with a low opacity setting to do this) and to add some smudginess, either in a vertical or horiontal direction. I often prefer the vertical kind because it creates an interesting contrast against the always horizontal surface.
To finish the surface we'll probably need some ripples and other "disturbances" here and there. A light border-like element between each object and their reflection works as a very efficient separator and some slight breaks in the reflections in distance helps to prevent a too unnaturally peaceful surface. No pure white, instead pick a light version of the color you're painting on.
And then we're done and it's time for a snack. Finally, it's been hours!