I'm real big on instinctive cooking. I'm also the same way at the gym, I show up with a pre-conceived plan of what muscles to work and that's it, I don't have a routine all planned out, I show up and see what equipment is available and go from there. The same applies in a kitchen. At any given time, you will have different ingredients to work with. So, it's all about nutrition, efficiency, cost effectiveness, and of course being tasty.
My generic tips:
(1) Keep as much good "raw materials" around as possible. Shop from the perimeter of the supermarket: (A) Fresh lean meats, (B) Fresh Organic Dairy/Eggs/Cheese, (C) Fresh Fruits and Veggies, (D) Fresh whole grain breads
(2) Use smart balance, or olive oil, not butter or margaine.
(3) A complete meal consists of at minimum 1 serving of protein (meat, tofu, egg, cheese, whatever), 1 serving of carbohydrate (bread, pasta, rice, potato), and 1 serving of vegetable or fruit. If you pick 1 of each category that intuitvely will taste good together, you are on the right track.
(4) I am pretty brutal when it comes to demanding the most amoutn of benefit from the least amount of effort. My favorite base of ingredients in the world to add to anything is: 1 red pepper, 1 green pepper, 1 vidalia onion, 1 package of portabella mushrooms, 3-4 minced cloves of fresh garlic, dash of salt and pepper, cook it all up in olive oil.
You can add the above to chicken, steak, pork tenderloins, salmon, whatever, THEN pick out pasta, bread, or rice, and VOILA! You are done. The meal is tasty, nutritious, and you look like a genius. Serve with wine if you want to get laid.