Illustrator Workshop

DPI - Dots Per Inch.
zoom into photoshop you can see pixels.
lower the Resolution the bigger the pixels.
Optical mixing. 
Chuck close. Artist. 
300 Resolution = Standard in Photoshop.
vector
mesh
smooth crisp lines
paths = lines
press space bar, hold and click then you can move the screen around. 

pen tool = main tool
cmd + and _ = zoom in and out
cmd z = undo
press 'i' then click on a section with the colour you want to get the matching colour