To refine edges further use the quickmask mode 
(q). This button is found second to bottom on the tools menu. A red film appears if something was already selected (Img 10c).
Everywhere that isn't red gets selected when you exit quickmask mode.
The red part does not. You should only go into quickmask mode when you
want to select things, as many options are turned off when inside this
mode. Some times when photoshop doesn't seem to be working, check to
make sure you didn't accidentally put yourself in quickmask mode by
pressing q. Leave the mode and all returns to normal.
To change what's red you use the brush (b) To increase the Brush size press ] and to decrease press [. Press Shift + [ or Shift + ] to control how feathered the brush edge is. Further brush options and Img 10d) and the brush window (Window>Brushes) There's a lot of options and to find out more on them you can go to my painting in Photoshop tutorial. To change the opacity of a brush simply slide the slider in the Options Window or press 1 to set the brush to an opacity of 10%, 2 for 20%, etc. when the brush tool (b) is selected. This opacity option works the same as layer opacity, for those who have been paying attention.
To switch between black and white (the two colors you're allowed to paint in with quick mask mode) press x or click the arrow 
that switches the foreground and background.
Exit quick mask mode by pressing the icon (q).
Quick Masks work on the same principal as masks. The difference is that while quickmasks you paint the selection, and then go on your way, with masks you can save this selection (in the form of red on blank or black on white in the layer's palette) you've created and continue to adjust it later. Quick Masks would more acurately be named one-time-use Masks, but that doesn't really have the same ring.
To use a mask simply make a selection in one of the plethora of ways discussed above and click the mask button 
at the bottom of the layers window (Img 5). In the layers window a black and white box is created (Img 11
- the word 'MASK' and a smile face are in that box. I did that, they
don't come standard.). In the picture you can see it's selected by the
is Mask selected, while 
is layer selected. If you're still confused about what exactly masks do, take a look at Img 11a where I've pictured to the main window and palette window showing the same picture with and without a mask.
To select between the layer and the mask, simply click the layer or mask icons. Use the brush tool (b) to affect the mask as desired. X is still a good way to switch between the foreground and background colors. d make the foreground and background colors black and white respectively. You can also click on the colors to select which color you desire. Click on another layer to paint with the brush on the actual layer rather then just affecting the mask. You can always click back on the mask to edit its layer again (make sure to click directly on the black and white box in the layers palette - otherwise you're just selecting
To get rid of a mask you can drag it down to the trash icon at the bottom right of the layers palette or right click the mask in the layers palette and select 'Delete Layer Mask'.
Some tecniques still worth learning for selection that I won't be going into are Paths 
and Alpha Channels (Window>Channels). I think a half dozen approaches should be enough to quench your thirst for knowledge for now.
So now use that Lasso as only you know how and trace out the head, Moving it to where it needs to go in the image. You've learned a bunch and there's one step left in this intro tutorial of all that is Photoshop.
