1. You use poor quality ingredients.
Poor quality cooking ingredients are only going to produce one thing, a poor quality cooking outcome. The foundation of all good cooking is the use of top quality ingredients. The following are just for a few examples of what this means.

Vanilla. When a recipe calls for vanilla, there is no substitute for pure vanilla. Imitation vanilla does not even come come close in quality of taste to pure vanilla.

Butter vs. margarine. When a food recipe calls for butter or margarine, always use butter - preferably unsalted. Read about salted vs. unsalted butter butter to learn why. Do not use margarine in place of butter. Margarine is a very poor substitute for pure, sweet cream butter. It will effect both taste and texture of the foods you are cooking or baking.

Baking soda or baking powder. Check the date on your containers of baking soda and baking powder to be sure it is fresh and not expired. Never use baking soda that is being used in the refrigerator to absorb odors.

Nuts and seeds. Nuts and seeds tend to go rancid in a fairly short amount of time. Do not purchase more nuts or seeds than you will use in the near future and check the expiration date before you make your purchase.

Spices. Spices should be fresh and carefully stored in a cool dry place in a tightly sealed container. This is especially true for green spices like sage, thyme, marjoram, rosemary, parsley, savory, oregano, basil, cilantro and others.

Flour. Use good flour appropriate for the recipe you are working with. For instance, if a baking recipe calls for cake flour, only cake flour will do. Check the expiration date on the package before you purchase flour to be sure it is fresh.

Produce, meats and dairy products. These items deserve your utmost concern when purchasing so make sure they are fresh and of the highest quality. Then, take good care of the items when you get them home. Store everything carefully and with respect for the product. This will maximize quality and reduce waste.

2. You use cold eggs instead of using eggs that are at room temperature.
Believe it or not, in the case of frying eggs, cold eggs used right out of the refrigerator will have more of a tendancy to stick to the frying pan than if they had been used at room temperature. Using cold eggs in many baking recipes can also contribute to a poor outcome. Simply take eggs out of the refrigerator about 30 minutes before you plan to use them so that they are closer to room temperature. You can also place eggs in slightly warm water for 5 to 10 minutes and achieve the same results in much less time.

3. You do not know your oven well.
Every oven is different. Electric ovens, gas ovens and even wood stove ovens all perform differently from one another. Baking success depends upon how well you know your oven. For example, does your oven sit level? Is your oven calibrated to temperature correctly? You should learn about and be very familiar with how your oven performs.

4. You do not measure ingredients accurately.
There are no short cuts to accurate measurements. Ingredient measures matter in all recipes. Measure all cooking ingredients carefully and accurately. Do not pack dry ingredients into a measuring cup. Spoon flour into a a dry measuring cup (a cup without a spout) and then level it off gently with a straight edge knife without packing the flour into the measuring cup.

Use the same care with teaspoon and tablespoon ingredient dry measurements for things like salt and spices. Don't heap or pack the amounts. Just lightly scoop an amount and level it off with a straight edge knife.

5. You do not allow a pan to get hot enough before adding food.
When sautéing vegetables, browning meats or pan cooking fish, poultry or sea food making sure the pan is properly hot before using is very important. The pan will perform better and food will be less likely to stick.

6. You go out of hearing range of the cooking timer.
How many batches of cookies have been ruined because the 10 minute timer went off while you were in a location where you could not hear it? Just carry a portable timer in your pocket if you have to leave the room where a cooking timer has been set. That way you will always know exactly when your attention is needed!

7. You grill or oven bake meat right from the refrigerator.
Meat should be room temperature before you cook it. This way meat will cook evenly an as the recipe indicates. Simply set meat out on the counter for about 30 minutes before cooking for best results. Be sure cuts are in a single layer (un stack steaks for instance) and keep covered with plastic wrap during that time.

8. You boil instead of simmer.
Soups, stews or sauces should never be boiled at all. Cooking time should be at a carefully monitored gentle simmer throughout. Boiling simply has a ruinous effect on food. There is an old saying that is timelessly true; "soup boiled is soup spoiled. This applies to sauces and stews as well.

A simmer is achieved when very light bubbles break the liquid surface every few seconds. This gentle cooking action brings out the best flavor of foods and can not be rushed.

9. You allow milk to boil.
Milk can not be boiled. If it is boiled it curdles. When a recipe calls for milk to be scalded, the milk must be heated very slowly and very gently and constantly stirred.

10. You don't follow the recipe.
A reliable recipe needs no improvement, so stick to it. If you want to try experimenting with altering cooking recipe ingredient measurements or making substitutions, do so on a planned experimental day when the cooking results are not being depended upon. In other words, don't experiment with a cooking recipe on an evening when guests are expected for dinner, or on the day a birthday cake has to done just right by a certain time. Prioritize your efforts.