Lots of great advice in here. Especially about spices. You can cook the same things but swap spices, and it will be like a whole new meal.
Invest in some different vinegars to make your own dressing, that you can control the sugar content or use whatever sweetener you like.
Use fresh citrus to brighten flavors. I hate bottled lemon juice, but use that if you have to.
Roast your veggies, root vegs, broccoli and cauliflower- olive oil, salt and pepper, or spice up how you like. Either in the oven, or on the grill. I toss my broccoli and cauliflower with sliced fresh garlic after it's done.
Eat your beans!
Get a food scale.