oh do you mean cropping yourself off the picture?
and then making a separate photo?
1. Open the photo.
2. Using the lasso tool, magnetic lasso or the polygonal lasso tool.
3. Move around the image (or in the case of the polygonal lasso tool, click every point that you want to select)
4. Connect the last point to the first
5. Click enter
6. Drag or cut the cropped image to a new file. (create a new file)
7. Add your effects