I am by no means a master chef, however, I love food, appericate the art of cooking and also enjoy trying new things.
With that here is what I can offer (just personal thoughts)
Don't ever skimp. There is a lot of talk about low fat, etc, but I have found that the recipe will turn out the best if you use what is called for. If it requires butter, use butter, not margerine. I think it is better to eat a little bit of something "bad" for you than a lot of just... "ok" food.
Never fear experimenting. Worst case, the dish turns out badly, a few dollars are spent, but as long as you learned from the expericnce, it was valuable. Remember or write down what spices you like together, which herbs work well with what meats and veggies.
Handle food with care, especially MEAT. Get cutting boards that are assigned to just meats, one for poultry and another for fruits and veggies.
Learn about food safety. Know what temps are proper for each meat. However, many temperatures for certain meats (pork for one) are a bit, over-cooked. Do some research.
When cooking most meats, when you take them off the grill/out of the oven/out of the pan, let them rest for at least 10 minutes to the juices can reconstatute and that will make your meat much more tender.
When possible, use fresh foods. In a pinch, frozen is fine, but fresh always will taste better.
That is all i can think of now... but if you have any specific questions ASK!