Save all bones from any meat you use. If you roast a chicken, duck, lamb chops, etc. freeze the bones until you have enough to make a decent amount of stock. This is the KEY to those wonderful sauces everyone loves.
Cold dulls flavor, so if you are making something that will later be chilled or frozen, such as ice cream, the flavors should be slightly bolder to compensate for this.
Acid brings out the flavor of fruit. Have you ever noticed there is always a bit of lemon juice in fruit desserts, apple pies, compotes, and chutneys.
It is important to understand that poach, simmer, and boil DO NOT mean the same thing. Poach is when the cooking liquid is 160-180 degrees, simmer is 185-205 degrees, and boil is 212 degrees.