A brand new and improved tutorial/walkthrough on drawing a detailed fairly realistic eye. C: I didn't focus that much on how to get the shape right, but more on colouring and effects. I hope it helps, and if you have any questions ask away!
I guess you need at least a little Photoshop or any other art program knowledge, as I'm not showing which button does what and all the settings, etc. I am only demonstrating my technique.
Yes, this was all done on one layer. That's why there might be smudges over the iris while I'm actually working on the eye rim.
Suggestion- If you're drawing yellow eyes, make sure to draw them a different colour first and then change the hue. Yellow dodges horribly and will look ugly.
Used Adobe Photoshop CS3 and a tablet. Doing this with a mouse would be crazy, especially the little details and everything, but you can try. Any art program can be used as long as it supports dodge/burn and pen pressure. Sure, you can try doing this with different colours instead for a more natural look, and with a very low opacity brush if you don't have a tablet, but that's going to be a nightmare. Seriously.
And now don't ask me for a tutorial on colouring fur/backgrounds/etc, as I do it mostly the same way as here. Sketch, base colour, shading, highlights, details, finalizing.