As a Sample Project, I took this leaf to and Isolated it from the background.
I hope you like it, and look forward to see your projects.
Image with a background of the gray/white squares (Photoshop way of showing transparent layers in the program)
Image with actual transparent background (PNG file)
An Animated GIF showing the Before and After (Link to class, for If you want to lean this technique -> Create Simple Before and After Comparison Animation in Adobe Photoshop )