Follow the directions exactly, especially when baking.
Have good tools. Make sure your knives are sharp, your pots are in decent shape and get an oven thermometer. Know your oven, the back left may be hotter than the front right. The whole oven could run 10 degrees off. You won't know if you don't use a thermometer.
Practice and tweak. Make the same dish a few times and alter ingredients and cooking time to perfect it. Think about what went wrong and what you can do about it. Realize that weather can effect the turnout of your food, especially candies and baked goods.
Don't over complicate it and start off with easy dishes and progress to harder things when your ready.