I've based this tutorial on the Microsoft Paint program. It contains the basic facts to get you started with creating your very own electronic paintings or your designs. Some of the screenshots have textual explanations within them, which should help to clarify some of the actions you need to perform to complete your task.
Creating an electronic painting is actually not that different from painting in the traditional way using oils or acrylics, albeit far less messy. Both the electronic and traditional ways of painting use light and shade to build up the whole perspective, and with practice an electronic painting can look just as good as a traditional one.
Mother Nature is the greatest artist planet Earth has, and it's what she shows to us on a daily basis that inspires painters to paint. Electronic painting is no exception and should copy her style in the same way as she displays it. But instead of using brushes and colours on canvas or paper, the electronic painter uses the mouse and what the colour palette in paint programs has to offer. The only limitations to any type of artwork, is your imagination. Experimentation is the key word here. And as with all experiments, there'll be failures as well as successes.
If you're new to Paint Programs, then following these basic instructions should be your starting point [using Microsoft Paint].
Click on Start. Point to All Programs. Go to Accessories, then click on Paint. You'll be presented with a blank page as shown below.

Now you'll need to go to the File Menu and select Page Setup as shown below.

Notice that the Orientation is set to Landscape. The highlighted box with what looks like an envelope shows how your painting will be positioned on the blank page. Don't worry about sizing your picture at this point as it does not matter to us right now.
Should you require further instructions at this point in time, then go to the Help Menu and click on Help Topics. Here you'll find an extensive range of topics to assist you.
The Colour Box at bottom left is the place to select the colours you wish to use when creating your painting or design. The 2 little boxes at the far left of the Colour Box are the Foreground and Background colour boxes. The top black box is the Foreground colour, the bottom white box is the background colour. These colours are the default colours when Paint is opened for the first time.
The top box [foreground] is used for lines, borders, shapes and text. The bottom box [background] is used to fill the inside of shapes.
You can change the colour of a line if you click in the Toolbox [top left] and click Fill With Colour [the Paint Can] and then click the line you want to change.
But for now let's assume that all you really want to do is to get started on creating a painting. So let's move to the next step.
You'll need to fill your blank page with a sky colour. Select blue from the Colour Box, select the Paint Can [highlighted] and click in the page to Fill With Colour.

As you can see in the above photograph, the Paint Can [Fill With Colour] has been highlighted in the Toolbox to the top left.
No doubt by now you've already been hovering your mouse pointer over all those different Tools and discovering what they're called as each one is highlighted. If not, please take the time to get to know them.
For this tutorial we're going to need only 3 of those Tools; the Pencil, the Spray Can, and the Paint Brush. Trust me, using only these 3 Tools you're going to be able to create wonders, and probably astound yourself at your capability.
I ought to mention here that creating an electronic painting is all about mastering the technique of using the mouse. If you know the tricks, it's easy. So here are a few tricks I've learned by experimenting with the mouse. Practice makes perfect.
When creating river banks or hills, use a downward arcing stroke with the mouse. For flowing rivers or still water, zig-zagging across an area with colours really makes the water effect stand out. Do the same to show sunlight reflected on the water. Zig-zag the mouse for reflections and shadows of foliage.
In time you'll discover new ways of using the mouse that you didn't think possible. Now let's move forward to the next stage.
Editing colours is your way of adding different hues to the Colour Box. Below are 2 photos concerned with editing colours. Both contain textual explanations.