Effects
Without ever using an effects pedal it's possible to get some amazing sounds from a guitar with a little practice.
Once you have become fairly comfortable using a pick you can try holding it in a slightly different way:
Allowing the thumb to slip along the pick a little means that the green area can 'rub' lightly on the string that the pick is playing. Doing this can produce tonal effects like cross-phased pickups. It can also produce a damping effect and harmonics. I find this works best if I'm picking the string about 10 to 12 cm above the bridge - moving up and down the strings gives different sounds.
Another effect can be achieved by allowing the side of the hand (purple area) to touch the strings close to the bridge. This 'dampens' the note being played.