Try adding nuts to foods: slivered almonds on cereals and desserts, peanuts or cashews in casseroles and stir-fry. I really like to make that green-bean casserole (w/mushroom soup and french-fried onions, the one that always turns up at potlucks) substituting salted peanuts for the onions that get mixed in and only using onions on the top.
Learn to make a spicy peanut sauce, and eat it on pasta, veggies, salads, etc. I put some peanut butter in an empty glass jar; microwave briefly to melt it; add soy sauce, cider vinegar or lime juice, cayenne pepper, garlic, and ginger; and put the lid on and shake. Yum!
Beans! Make burritos or taco salad or bean soup or hummus. Sprinkle beans on salad.
Tofu is good in practically any recipe that calls for boneless chicken: teriyaki, baked in sauce, tetrazzini, paprikash, etc. The great thing about it is that it soaks up flavor (marinate overnight for even yummier results) so can be used in practically any style of cuisine, not just Chinese.
Have you tried tempeh? It's a soy product with a consistency (and price) somewhere between ground beef and cheese. Tasty grilled, or in any recipe where you would use strips of meat, or on a salad.
I love cheese and add it (usually low-fat mozzarella) to spaghetti, rice dishes, steamed veggies, etc.
Do you eat eggs? One of my new favorite recipes: Start cooking rice. Slice up zucchini and a little onion and saute in plenty of olive oil and herbs. Put rice on plate and put zucchini over top (lifting out of oil w/slotted spoon) and cover to keep warm. Scramble 1 or 2 eggs per person in leftover oil. Put eggs on top of zucchini. It's a one-plate meal! I also like "breakfast burritos" w/egg, cheese, and salsa at any time of day.
Eat yogurt as a snack.
When you really must have sweets, eat ice cream! Then at least you're getting protein and calcium along w/your sugar.