1. Not all bread crumbs are created equal. Different brands have different textures and different textures will change the texture of the meatballs. Look for "flaky" breadcrumbs rather than coarse or dense kinds.
2. Add the milk last and in moderation. The different types of ground meats vary greatly and some will require less/more milk than others. Start with 1/2 cup and add more if the meat mixture is not holding together well when meatballs are formed.
3. Meatballs can also be made on the stove top. Start by adding a light layer of olive oil/butter over medium heat. Add the meatballs and brown on all sides. Reduce heat to medium-low to finish the cooking process.