Here's my secret: Don't light the oven.
Why this works: food that can be steamed, boiled, fried or cooked in a pressure cooker (that is, cooked on the stove top) tends to be fast and easy to prepare. Food that doesn't need to be cooked at all tends to be even easier. Baking and roasting, on the other hand, take a long time, and the recipes tend to involve a lot of steps. It heats up the house, too. Living in a house without central air conditioning, I'm opposed to lighting the oven in the summer. Baked and roasted recipes often make a lot of food, too. If you cook just for yourself, you might not be able to eat all the leftovers in time. Stove top cooking lends itself to individual portions.
This rule also helps steer you away from making bread, cookies, cake, brownies, lasagna, pie, pizza, noodle casseroles, baked potatoes, and other high-carb junk.
Food I make using this rule: omelets, deviled eggs, sausage, bacon, burgers, steamed veg, cheese sauce, fried chicken, salad, salad dressing, a small roast (cook it in the pressure cooker--a good dish if you have company), liver, braised oxtail, kelp chips, steamed veg, ranch dip, fried cabbage, sauteed mushrooms, no-hidden-carb fudge, pate (for special occasions--it involves a lot of steps), a veg/olive/cheese plate, and any kind of soup.
Once in a while, I make exceptions to the don't-light-the-oven rule. I make low-carb pumpkin pie a few times a year, I soak and roast nuts (which is really easy), I broil meat now and then (which is fast), and I'll bake something if I really have a craving for it. But 95% of the time, I don't light the oven.