Icons may be a difficult task to develop. The size speaks for itself; you don't have much space to work with. But that's the fun of it: how do you make something aesthetically appealing, yet identifiable and basic, which more often than not is visibly very small. Consider what others are doing in your category, take your own ideas, and always do your homework on research. It's good to be on track of trends, but make the icon your own, because your icon will be vying for the user's attention with other icons, and sticking out is a necessity. The icon is the first thing users see when they meet your app on the App Store, and thus, your icon is one of the most powerful connections. It's what the users will connect with every time they use your app, and it will be the first thing that comes to their mind when they think of the app.
When it comes to colour, blue is a tried-and-true choice. Blue is the most popular and widely used colour in the world, according to numerous sources, therefore it's no wonder that its popularity is reflected in icons. However, you must select which colour or colours make the objective of your app stand out. Colours may be perceived in a variety of ways, and you can learn more about colour psychology here, here and here. Whether you utilize colour psychology or not, you should do some research to see what colours are popular in your app's category. Also, keep in mind how to use background colours efficiently - does a black or white background associate something valuable to your app or would a colourful one be the path for you?
Using just one letter
One very common trend among app icons is using only one letter in the icon, which more often than not happens to be the first letter of the app itself. This is a very popular way to simplify the icon and clear out everything unnecessary. However, how you create the actual letter may make your "simple letter" stand out. You can see a range of letters in the image above, some of which are bold and simple, while others are colourful and artistic. Even if it's "just a letter," there's still room for creativity.
Choosing one shape is one visual route that goes hand in hand with simplicity. This shape can also be anything other than just a square or a circle; you can be as creative as you like. Perhaps you'd like your app to be known as the one with the white bird? Yes, we've all heard of Twitter, but the white bird is simply a shape at the end of the day. It's as simple as that.
Leave out small details
After choosing the basis for your icon by the previous steps, make sure you don't overdo it. It might be hard to settle for something since there's always something you could do more. But as it goes with icons, ofter less is more.
If you decide to develop an app icon, bear in mind that it must function in a variety of situations and convey the core of your icon regardless of size. The app icon should be scalable, meaning that it should appear well at various resolutions. Overly complex icons that pack too much into the canvas are prone to scalability issues. For example, a successful app logo communicates with consumers without the need for words. Furthermore, when the icon's size shrinks, the text becomes illegible. Thinking about whether a particular design would scale smoothly, should take up a significant portion of the conceptual stage of app icon design. So go for simplicity and concentrate on a single object, preferably a distinctive shape, or an element that keeps its shapes and features when scaled, as previously indicated.
Less is more
Finally, go for bold and simple. Use bold colours and shapes, and let your creativity run wild. The actual challenge with icons is the restricted amount of space available for design. As a result, simplicity is critical, but it does not have to come at the expense of creativity - simple does not mean dull.
And as always, A/B testing is your best buddy.