The Ergons are nice because they have a slight taper to them (they get thicker towards the outside of the grip), which I have found to be pretty comfortable.
Another thing that can help is lever position but that is more trial and error. A lot of people set their levers in a position that feels good in a flat parking lot. The actual position they should be will be different on the trail and will be different for everyone. Look at the French guys! They run their levers almost horizontal!