Do not add salt to food at the table. The simplest approach is to put away all salt shakers and salt cellars so that salt is not around. That helps a lot.
Do not eat salty foods: potato chips, corn chips, cheese (quite high in salt), cured meats. Read the label on processed food products (foods made using industrial processes and sold packaged under a brand name). If salt is shown as an ingredient, don’t buy the food. These foods are hardly essential. You can buy low-sodium versions of some: soy sauce, tomatoes, vegetable/chicken/beef broth, etc.