Use a very sharp knife that will cut, rather than crush, the herb. When herbs are crushed they release some of their flavors, which can end up embedded in the cutting board.
Make sure the parsley is washed and dried thoroughly before you chop.
Don't worry about separating all the leaves of the curly kind before chopping. Use a chef's knife to cut off the large stems, then hold the bunch of parsley with one hand (with fingertips tucked under) and chop what's left.
-- From "What's a Cook to Do?" by James Peterson (Artisan, 2007).
For a clean trim, cut off any feathery stalks diagonally so that a V shape forms at the point where they meet the top of the bulb (as opposed to cutting them straight across). To prepare the bulb, cut a thin slice from the bottom end and discard. Pull away the tough outer layers, on the left and right. Make two cuts on the bottom, forming a wide and shallow V, to discard the core.
Another prep tip: If the fennel will not be used right away, soak the cut edges in acidulated water to keep them from turning brown.
-- The Washington Post