Never bathe or shower in hot water. Lukewarm is as hot as the water should be. Use mild soaps such as Dove or Basis. Gently pat the skin after washing. While it is still damp, apply a moisturizer.
Petroleum jelly is effective and inexpensive, though some find it too messy.
Lubriderm, Aquaphor and Nivea are other good moisture-retainers. Don't wash with harsh detergents. Use two rinse cycles on each batch of clothes. With winter approaching, be sure your home has enough moisture in the air. Hot, dry air promotes eczema's return.