As flycatcher pointed out edema can have many causes....the problem to solve is what is causing the edema and treat that before doing anything else. It is dependent on your health status, age and medications, prescribed and OTC, that you are taking. Since the solution could be very different depending on whether it is due cardiovascular, lymphatic, renal, inflammatory or electrolyte imbalance a visit to the doctor is called for.
Certainly cutting down on salt is essential. I'm assuming you have heard from a health professional that you need to take steps to eliminate edema.
Other measures are good phama drugs, like lasix, and your doctor would mix in Potassium supplements as well. Edema can have a number of causes, not only cardiac issues, so certainly I hope you have talked to your doctor about the root of your problem. Also, this is a conversation you should have with a dietician.