It's highly recommended to use IconThief with WhiteLine Icons.theme selected in the dropdown list in order to make sure that no icons are mi

Icons should be no smaller than 50x50 and no larger than 60x60, floating inside a transparent 114x114 square (or 118x120 for System icons.) The best way to achieve this is to work inside a 60x60 image, and then change the canvas size to match your icon.

The easiest way to turn a simple logo (such as the Nike swoosh, or the  Evernote elephant) into a WhiteLine looking icon is to look online for a vector of that logo, use the smart eraser tool with a low tolerance to delete the area around the icon, meanually clean up the feathering around the logo, and then resize it to somewhere around 55 pixels at it's largest dimension (in order to make room for the drop shadow.) Next, use the B&W image adjustement to make the entire logo white, then use the dropshadow template included in the .psd to finish the icon (don't forget to set the light angle to 122 degrees!)

For more intricate logos that can't simply have the backgrounds smart erased, use the pen and direct select tools to trace the logo by hand, with the brush set to 3pixels (feathered) for thin lines, or use the shapes tool if it's a logo comprised mostly of simple geometric shapes.

In order for things like Auxo previews and Notification Center icons to look right, the 29x29, 58x58, 40x40, and 57/58x57/58 icons should take up the entire image.

Lastly, if you successfully create a handful of great looking icons, please consider sending them in so that they can be included into an update for others to enjoy. You can email them to whitelinetheme@gmail.com :)