If you are not good in drawing you can create icon from existing image. You only need to cut or compress it to required size, adjust sharpness and save in icon graphic format like ICO or GIF. SoftOrbits Icon Maker can do the entire job by itself.
Open the original file inside the program using 'Open an Existing File' option in the start menu. Here you have a few options - you can create an icon for Windows, iOS or Android. Depending on the target OS, click on the proper icon on the tool bar. You will be offered to choose available sizes. For instance, if you choose Windows format, you can select 16x16 to 256x256 px size. A number near each resolution means color depth, from 4 to 32 bit. Everything is very straightforward, just check off required resolutions. There can be a lot of sizes checked at once, this is a batch icon create program that is capable of generating multiple icons from a single image. It can also generate icons from multiple images at a time.
You will see all generated icon variations to the right from the work sheet. They all can be tuned by graphic filters and drawing tools. To see how specific icon resolution will look in real size on the screen, use zoom tool. This way you can select the most suitable variation and create an icon from appropriate draft. SoftOrbits Icon Maker is full of graphic adjustments for tuning colors, contrast, sharpness, etc. There is an option to create icon for disabled mode. As opposite to an active icon, the disabled one is greyed out.