Use meat sparingly (it's expensive!) to make things more exciting, and always put onions, garlic and [all kinds peppers[1], zucchini, fennel (the bottom parts), herbs[2]].
All of those ingredients last in the fridge and can be "revived", or cooked when they're starting to go bad. If you're new to feeding yourself all of your meals and having food in the fridge all the time, the tendency to buy fresh products that rot in the fridge is high. These ingredients let you cheat a bit.
Olive oil and salt and pepper should be liberally applied to all of this.
Finally, on the the health front, you'll probably cook more than you need – this can cause overeating. I usually portion food into a storage container before I start eating, forcing me to control portions. When you start cooking all of your food and controlling your portions, you realize more what your body needs and honestly how little it actually requires for sustenance. Rich world countries eat such an incredible amount of food.
My two cents! This is a personal thing, so your mileage may vary, but hope it's a bit helpful.
[1]: I live near a substantial hispanic population, so all sorts of interesting peppers exist that can change meals completely for very little cost and effort. http://en.wikipedia.org/wiki/Capsicum
[2]: Depending on your market and the season, herbs can be relatively affordable or completely absurd. I only buy it if it's fairly priced, can be a real gouger.