The best method to avoid oversalting is to taste your food that is before adding salt to your food. But even if you have taken these precautions and your food still tastes like a salt lick, there are a couple of things you can do to make your food seem less salty.
First, try to trick your tongue into thinking the food is less salty by adding acids like vinegar or lemon juice to your food. Another trick is to add a little sugar to your food. If you are making soups or broth, adding water will help. Do not bother trying to add potatoes to salty dishes because it does not work and picking potatoes out of your tomato sauce is not fun.