Let's discuss purely technical details of icon creation
1. Lines, angles
One of the vital parts of the image is the framework of the object, i.e. rough border, which limits the object from the rest of the image. When working with large-scale images, the artist occasionally thinks about defining objects with complementary lines. This is unnecessary because of the scale: even low contrast objects do not blur into a one. Pixel graphics is other story. Two solutions are possible: either foreground and background colors have to be from opposite sides of the color chart, or the object must be separated from the background by contrast outlines and shadows. I would like to dwell on lines in more detail.
If we return more to the big-size graphics, we see that in order to highlight contours, we can use all (even the most complicated) angles, Bezier splines and edges. Anyway, the line will appear ideal thanks to anti-aliasing. When shrinking the image dimensions to the size of an icon, situation changes greatly. When each single pixel is equally important and can ruin the overall appearance of the composition, anti-aliasing is just not applicable. It means that you have to consider the possible line angles.
The angle you select for the line, specifies the step for this line. Because each line consists of primary elements, the union of which determines its accuracy and visual appeal.
For example, a 18-degree angle contains many small 3-pixel lines combined with a 1-pixel downshift:
This is how nearly every line looks like. Basic element with joining and second primary element. However, not every angle creates lines that look look attractive and not messy.
For example, look at 25 and 20-degree angles:
It can be easily seen which line is more attractive. The 25-degree slope produses a line consisting of even 2-pixel primary elements. The 20-degree angle has a primary element containing of three lines: 3-pixel, 3-pixel and 2-pixel. The slope is more complex, therefore, if not combined by other visual effects, it creates a feeling of messiness: the primary elements have contrast which is too obvious to hide from the human eye.
Now we can come to the first conclusion. The most "appropriate" slopes have to make as plain basic elements as they can. Thus, the ideal slopes are 0 and 90 degrees. In them, 1-pixel basic elements are joined without downshift and form smooth lines. Less ideal are slopes which form basic elements of 1, 2, 3 pixel with 1-pixel downshift. Of course, the lines will not be even, but the human brain will process the picture and provide to the viewer what you intended to show to him. Also, the mentioned angles can be considered acceptable (but at a stretch): angles with primary elements made of unequal lines shifted by more than 1 pixel.
It is the time to discuss another issue. In the last paragraph, I intentionally defined angles with basic elements of 1, 2 and 3 pixels as acceptable. Such tiny lines, especially when a large amount of them is combined, look like a single whole. But what do we see if we change the primary elements to 10 or 20 pixels?
Here is an example:
It can be clearly seen that the line loses its solidness. It is not a continuous line anymore; it is a set of several lines, located near one another. Rarely any artist wants its creation to look that way. So, we come to the second rule: if you use minimal angles, which make long basic elements, it has to be justified and employed with maximum caution.
And, finally, the third thing I have to tell about lines. I already wrote that the primary element has to be as plain as possible.
For instance, a 25-degree angle can be drawn in the two (sure more of them exists) following ways:
In the first picture the basic element is a 2-pixel line. In the other case, it is made of three elements: 3-pixel, 2-pixel and 1-pixel. The same slope but the look is different. The complex basic element made the line messy.
This examples can be produced for about any angle, so in your projects, try to simplify everything.
It can be stated without an overstatement that the color is the main aspect of your work; not suiting or poorly matched colors can kill even the most creative idea. What can we say about the color in miniature graphics?
First, there is a clear rule: if the picture looks bad when reduced to grayscale, it means the colors that were selected are incorrect. This rule is valid not only for icons but for the whole graphic design.
Second, you will probably unable to apply common RGB. Sure, you can use GIF colors only, but this limits you greatly. Gradients, shadows, dithering and many other effects will not be accessible to you.
Third, try to enlarge the portion of "plain" color. The more evenly colored areas without blurring and jumps your project has, the more neat it looks. Pictograms are too tiny and the over usage of special effects makes the image look messy.
Fourth, gradients. This is a wonderful tool which can improve the look of any picture. Besides esthetics, gradients are a perfect solution to get rid of the "broken line" look (lines with too long primary elements). But be attentive when using them since too many gradients can ruin the plain color, and be unable to fit into the gif palette.
Fifth, shadows and flares. All aspects of using shades and highlights in icon creation are completely identical to the aspects of the overall graphic design. The only thing I would like to mention: draw everything yourself. Don't use filters, make all shadows and highlights in a different layer and then edit its transparency. If applying effects, you rarely can predict what the result will be. It is bad when you don't control the process of creating of a composition. It is worse if you can't control it when creating miniatures.
And, finally, sixth. Nuancing is the main aspect of pictogram creation, which greatly affects the esthetic look of the composition. If the blue human eye in the picture has the size of 1 pixel, increase the color intensiveness. For example, instead of 0, 131, 159 choose 71, 195, 242. It is indifferent that the human eye never has such color; in the first case it will appear like a gray dot, and in the second example it will definitely be a blue eye.
completely control the image, do not allow the visual illusions to ruin your design. It is OK if objects is not consistent from the technical point of view, but the whole picture must be flawless.
As an example, I drew the pack of juice located before me. The picture has flat color, gradients with broken lines, shades and highlights and nuances.
If I talked about something other than miniature design, this part wouldn't fit into an entire book, but the resolution of pictures ;limits fonts too.
The resolution of symbols is the main aspect as opposed to their beauty. Almost in any case, unless the letters are the main part of the project, the font size must be reduced to the largest extent possible.
In principle, virtually any design company has its own font with little characters. Such a font can be made in a few hours. You can browse the internet and collect your own library of very nice fonts. First of all, I would recommend you to get the DS Pixel and Seventen 7Vedi webpage as well as the whole set of fonts from the Lakmus Lab website.
If you don't want a new font, little typesizes of Arial and Verdana will work. As a last resort, you can draw the needed characters yourself.
There are not many rules there. First, letters cannot be less than 5 pixels high or less than 3 pixels wide.
Second, letters should not use anti-aliasing. It turns the text into an unrecognizable set of pixels.
However, there are no rules without exceptions and the 5-point Arial looks perfectly readable.