Some of the ways I cook at home were bound to change once I started culinary school. I expected that. I wanted it. What surprised me was how significantly a few small tweaks changed the quality of my food. I've already talked about using homemade stock, clarified butter, kosher salt and white pepper. Here are a few other things that have had a great impact. (Be gentle - it's hard to admit a few of these.)
Fresh garlic. I tabled my garlic press when Trader Joe's came to town. The appeal of the jars of minced garlic was too strong. But I'm back to the real thing.
Fresh herbs. I've always grown (or purchased) fresh basil and parsley, but I relied on dried thyme, oregano, dill, etc. Now it's rare for me to go to the spice drawer unless I'm baking.
Air cooling. I used to cool potatoes for salads under cold running water. Now I simply lay them on a baking sheet (with a bit of olive oil) and don't run the risk of having them get waterlogged. I use the same technique with pasta. The sauce sticks better and the pasta keeps its starchy flavor.
Smoking hot pan. In the past, if I even bothered to check if oil in a pan was ready, I would look for some wavy motion in the oil or just put in a tip of food in to see if it bubbled. And food often stuck to the pan. Now, I wait past the waves until I see the oil starting to smoke. No more sticking.
Heavily salted pasta water. And I mean like the ocean. It seasons the pasta from within. It's also worth seasoning your vegetable water for the same reason.
Scraping and oiling the grill. I was just too lazy.
Guess you can teach an old cook new tricks.