Sprinkle on some nuts like walnuts, sliced almonds, or pecans, or some seeds like sunflower, pumpkin, or flaxseed for even more protein and fiber. Since they tend to be high in calories, just add about a tablespoon. Remember that although nuts are high in fat, it's the healthy fat your body needs. Plus the crunchy texture will make your salad much more exciting.
Source: Flickr User rhodes