Be sure to measure your ingredients carefully. Use metal or plastic nested cups for dry ingredients like flour and sugar, and graduated glass or plastic cups with spouts for liquids. If you use the liquid measuring cup for flour you may get an extra tablespoon or more per cup, which could make cookies hard and dry. To measure flour, lightly spoon it from the canister into the measuring cup and level it with a straight edge of a spatula or knife. Do not tap or shake the cup to level it. When measuring brown sugar, pack it firmly into the dry measuring cup so that it holds its shape when it is removed.