I work in Photoshop. I zoom in at 800% or so, and use the navigator to view how it looks at normal size. (It's a little off though, so I zoom back out to normal size every now and again too to check up on things). I use a soft edged brush, and the pencil tool (1px size) for adding small details and making the image look sharper. Part of the icons were made just by placing pixels one at a time. It can get tedious, but I think it does make a difference. I also tend to work on several different layers, so I can remove things from the icon if I don't like them later. Bear in mind I'm just new at this, and I'm pretty much making up my techniques as I go, xD but I hope that helps you.