Who is your audience?

First you must understand your target audience. If you're developing applications for kids you must make the application easy to use and easy to understand (ideally - nothing to understand). For example, consider eliminating text labels, popup menus and etc.

When I started developing My Little Artist the hardest task for me was to create the brush icons. The easiest way was to make text labels. But if a kid can't read or even if he can read - can he really understand what I mean by calling a brush "fur". I think I found a good solution - to draw on icons, things I can draw with that brush. Another benefit of not using labels is globalization of the application. There is a nothing to translate. And any kid, from any country can use this application. No matter which language he speaks.

How to hold user attention?

Kids like to draw, but not all of them can draw something interesting or artistic their first time. Kids who try to draw in a program with standard boring brushes and pencils, will find nothing special in it, close the application and forget about it forever. It is a important to help kid believe that he can draw really amazing pictures. Brushes and mirror modes in the My Little Artist help a young artists be more creative from the very first stroke.

On which devices?

Another impotant point - on which devices your programm will be used. With mobile devices an issue like battery life is a very impotant thing. Application must be optimized to use less CPU to preserve battery life.

During developing My Little Artist I used a trial version of VTune. VTune helps me to find the number of the performance pitfalls, and ways optimize my application. One impotant way to do this was to update areas only affected by stroke portion of the memory buffer. This allows me to reduce processor usage for some brushes for 50%.

Size of screen is another important thing. If you are using a 21 inch monitor there is no issue on how much space is used by toolbars. But on the netbook it matters. In My Little Artist I decided to use no top menus, with no window caption, and made the main window maximized. Ideally applications give the user, use of the whole screen. For that I added new features. I allowed for the main toolbar to be hidden when pressing the Tab button. Also the toolbar can be moved from left to right with just one click on the arrow button.

How to interact?

If your application requires use of a pointer device like mouse or a touchpad, make sure all of them are easy to use. Drawing with a mouse is comfortable on the netbook. But if a user has no mouse device make sure he can use the touchpad. I almost forgot about the touchpad when I develop my first version. Then I tried to draw something with touchpad and found that this is not as easy as with a mouse. To draw a user needed to tap twice on a touchpad and move cursor by moving finger across the touchpad. If the user removed his finger from touchpad to start drawing, he needed to tap twice. Or he needed to press and hold touchpad left button. Not so easy. To make it easier with a touchpad in My Little Artist I needed another way. And the way was found and implemented. To simulate left mouse button action, a user can just press the Spacebar, to release the left button just press Spacebar again. Nothing special, but this little feature will give user the ability to draw with one hand. Now drawing with touchpad can be easy as drawing with a mouse.

Keyboard shortcuts are a useful feature. Shortcuts can speedup some operations and make applications more comfortable to use. In the new version I deceided to implement shortcuts to support Undo, and Redo commands. My Little Artist is aimed for kids, so shortcuts must be easy to understand by kids. My simple solution is to map Undo to the left arrow key and Redo to the right arrow key. This is a easy to use, intuitive and easy to remember.