Here I get trampled by the angry herd. I put a small birdcage bell in their cage and they ring it now to let me know it's time for their hay. It only took a few times of feeding them hay and ringing the bell to train them, suprisingly. They also love chewable vitamin C pills, which are very good for guinea pigs. I feed them half a pill a day, so both of them will try to steal a whole pill right out of my hand before I break it up.
Audrey eats lettuce (Romaine, of course) like spaghetti - she just slurps it up. Lily eats slower, so I usually put in a little extra food so that there will be leftovers after Audrey gets full. They get lettuce, carrots, grapes, cucumber, apples, oranges... Both will eat right out of your hand, though sometimes one will try to grab and run with the biggest chunk of food she can grab. (They're both female.)