There are a few details which help make a crab or apple pick go smoothly:
1) When you arrive remove all the old apples from the ground using a rake, shovel or by picking them up. Hopefully the homeowner has a compost pile where you can put the apples (or you can take them to your own compost pile - or feed them to your pigs/chickens if you have them!)
2) Pick and collect as many apples as you can reach. These will be less bruised and keep fresh for longer.
3) Shake the tree to release all the unpicked apples. Collect all the apples on the clean ground (see #1). These will be slightly bruised and great for sauce, jam or juice.
4) Clean up under the tree leaving a nice, pleasant yard for the fruit-owner.
5) Divide the apples into thirds, give the fruit-owner their share. Deliver a third to a community organization (pick from this list), and then take your own share home.