Let's discuss purely technical details of icon design
1. Lines, angles
One of the most important parts of the composition is the framework of the object, i.e. solid linear marking, which limits the object from the rest of the image. When designing normal-sized graphics, the artist occasionally thinks about defining objects with additional lines. This is unnecessary because of the scale: even non-contrasted objects do not mix into a one. Pixel graphics is different. Two solutions are possible: either foreground and background colors have to be from opposite sides of the color wheel, or the foreground must be separated from the background by contrast outlines and shadows. I would like to discuss lines deeper.
If we think more to the big-size images, we can note that in order to define edges, we can use all (even the most complicated) angles, Bezier splines and borders. In any case, the line will look perfect thanks to anti-aliasing. When decreasing the graphic dimensions to the size of an icon, situation changes greatly. When each particular pixel is vitally important and can ruin the overall look of the icon, anti-aliasing is simply unreasonable. It means that you have to consider the possible line slopes.
The slope you select for the line, specifies the step for this line. This means that each line consists of basic elements, the union of which determines its accuracy and esthetics.
For instance, a 18-degree slope contains many small 3-pixel lines connected using a 1-pixel downshift:
This is how almost every line looks like. Basic element with joining followed by another primary element. Unfortunately, not every angle makes the line look neet and not annoying.
For example, here are 25 and 20-degree angles:
It can be easily known which line is more attractive. The 25-degree angle makes a line consisting of even 2-pixel primary elements. The 20-degree slope has a primary element consisting of three lines: 3-pixel, 3-pixel and 2-pixel. The angle is more complicated, therefore, if not supported by other visual effects, it brings a feeling of untidiness: the primary elements have contrast which is too strong to hide from the human sight.
Now we can see the first rule. The most "correct" slopes must make as plain basic elements as possible. therefore, the ideal slopes are 0 and 90 degrees. In those, 1-pixel basic elements are combined without downshift and produce smooth lines. Less perfect are angles which form primary elements of 1, 2, 3 pixel with 1-pixel downshift. Surely, the lines will not be even, but the human brain will process the picture and present to the viewer what you intended to show to him. Also, the mentioned angles can be considered correct (but at a stretch): angles with primary elements consisting of unequal lines shifted by more than 1 pixel.
It is the time to move to another problem. In the previous paragraph, I intentionally defined slopes with basic elements of 1, 2 and 3 pixels as correct. Such tiny lines, especially when a great number of them is combined, appear as solid. But what do we see if we increase the basic elements to 10 or 20 pixels?
Here is an example:
It can be obviously seen that the line doesn't have solidness. It is not a single line anymore; it is a combination of several lines, situated near each other. Rarely any artist wants its composition to look that way. So, we come to the second conclusion: if you use minimal angles, which make long basic elements, it must be justified and employed with great caution.
And, finally, the last thing I have to tell about lines. I already wrote that the primary element has to be as plain as it can.
For instance, a 25-degree angle can be drawn in the two (of course more of them are possible) following ways:
In the first picture the primary element is a 2-pixel line. In the second picture, it consists of three lines: 3-pixel, 2-pixel and 1-pixel. The same slope but the look is different. The complicated primary element made the line messy.
Such examples can be made for about any slope, so in your works, make sure to simplify as much as possible.
It can be stated without an exaggeration that the color is the main aspect of your work; improper 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 certain rule: if the picture looks bad when reduced to grayscale, then the colors that were used are wrong. This rule is valid not exclusively for icons but for the entire graphic design.
Second, you will be unable to apply safe RGB. Of course, you can select internet colors only, but this ties you hand and foot. Gradients, shadows, blending and many other effects will not be accessible to you.
Third, try to increase the areas of "flat" color. The more evenly colored parts without blurring and jumps your picture has, the more neat it appears. Icons are too tiny and the excess usage of special filters makes the picture look messy.
Fourth, gradients. This is a wonderful instrument which can change the look of any picture. Other than esthetics, gradients are an ideal solution to abolish the "broken line" effect (lines with too long primary elements). But be careful when using them because too much gradients can kill the plain color, and be not suitable for the gif palette.
Fifth, shadows and highlights. All rules for using shadows and flares in icon creation are totally identical to the aspects of the overall graphic design. The only ine I have to note: create everything yourself. Don't use effects, make all shadows and flares in a different layer and then edit the opacity. If using filters, you almost never know what the result will be. It is bad when you don't control the making of a project. It is awful if you don't control it if creating miniatures.
And, finally, sixth. Tinting is the main detail of icon design, which largely affects the esthetic appearance of the project. When the blue human eye in the icon has the size of 1 pixel, increase the color saturation. For instance, instead of 0, 131, 159 choose 71, 195, 242. It is indifferent that the human eye can't have this color; in the first case it will look like a gray dot, and in the second case it will definitely be a blue eye.
completely control the picture, do not allow the optical tricks to spoil your work. It is acceptable if something is not perfect technically, but the whole picture must be perfect.
As an example, I drew the packet of juice located before me. The picture has plain color, gradients with broken lines, shadows and highlights and nuances.
If I talked about something bigger than icon creation, this chapter wouldn't fit into an entire book, but the size of pictures ;limits fonts too.
The size of letters is the leading issue as opposed to their look. Almost in all cases, only if not the letters are the primary part of the composition, the font size has to be decreased to the greatest extent possible.
In principle, almost any design studio has its exclusive font with small letters. This font can be made in a few hours. You can browse the web and collect your own collection of very nice fonts. First of all, I advice you to download the DS Pixel and Seventen 7Vedi website and the whole set of fonts from the Lakmus Lab website.
If you don't need a new font, little typesizes of Arial and Verdana may do. As a last resort, you can create the necessary characters by hand.
There are not many rules there. First, characters cannot be less than 5 pixels high or less than 3 pixels wide.
Second, letters should not use anti-aliasing. It transforms the font into an unrecognizable set of pixels.
Though, there are no rules without exceptions and the 5-point Arial appears perfectly understandable.