Use herbs and spices. Use different spices. I get tired of recipes that use the same 4 flavors over and over, so I look for recipes that use something else. Under-used spices I love: cardamon, rue, sumac. Under-used spices that I can only fit in certain recipes: caraway, mace, fennel seeds.
Get spice mixes for pre-balanced flavors, like Herbs de Provence, Garam masala or Harrissa paste (you can make this yourself, but you should try a few versions to figure out what you’re shooting for).
Maybe these are al old hat to you, but here are some standard examples:
add tarragon to tuna/chicken salad
add cardamon and nutmeg to cooked oatmeal and omit cinnamon