• Only fill the crockpot one half to three quarters full. The foods will not cook properly if the appliance is filled to the brim.
• Foods cooked on the bottom of the slow cooker cook faster and will be moister because they are immersed in the simmering liquid.
• An easy tip to check progress without lifting the lid. Spin the cover until the condensation falls off. Then it's easy to see inside.
• Remove skin from poultry, and trim excess fat from meats.
• You can thicken the juices and concentrate flavours by removing the lid and cooking on HIGH for the last half hour of cooking time.
• For food safety reasons, it's a good idea to cook on HIGH for the first hour to quickly bring the temperature up to 140 degrees.
  Then turn the dial to LOW and finish cooking. AUTO has the same affect on newer crock pots
• One hour on HIGH is equal to two hours on LOW.
• Add tender vegetables like tomatoes, mushrooms and zucchini during the last 45 minutes of cooking time so they don't overcook. .
• Remove cooked food from the crockpot or liner before storage. Because the liner is made of such thick material, the food won't cool down quickly enough to prevent the growth of harmful bacteria. 
• Follow the layering instructions carefully. Vegetables do not cook as quickly as meat, so they should be placed in the bottom of the appliance

Vegetables:
Dense vegetables like potatoes, carrots, and other root vegetables should be cut no larger than 2cm thick, placed in the bottom of the pot as they take longer to cook.
Liquids:
Usually liquids may be decreased in slow cooking - about half the recommended amount.
Unless the dish contains rice or pasta, one cup of liquid is usually enough.
Pasta:
If a recipe calls for cooked pasta to be added, cook it until just slightly tender before adding to the pot.
Herbs and Spices:
Chopped and ground herbs and spices tend to dissipate over long cooking times, so it's best to add them near the end of cooking.
Whole herbs release flavours over time, so are a good choice for crock-pot cooking.
Cayenne pepper and tabasco sauce tend to become bitter if cooked for long periods of time. Use small amounts and add toward the end of the cooking time. You should taste and adjust seasonings, if necessary, before serving
Milk/Cheese:
Milk, sour cream, and cream break down over long periods of cooking, and should be added during the last half hour unless the recipes states otherwise
Condensed cream soups are good substitutions for milk and can be cooked for extended times.
Healthy or reduced fat cream soups can be used in any recipe as a substitute.
Cheeses don't generally hold up over extended periods of cooking, so should be added near the end of cooking, or use processed cheeses and spreads.
Soups:
Add water only to cover ingredients in soup, and add more after cooking if necessary for a thinner soup.
For milk based soups, add 1 or 2 cups of water and during the last hour, stir in milk, evaporated milk, or cream as called for.
Thickening:
For casseroles and stews, thickening can be achieved by grating in a small potato near the end of the cooking time.
An alternative is to mix one or two tbsp of cornflour in a jug, mixed well with a bit of water. Add this to the dish stirring all the time till it thickens
Meal Preparation:
Over long cooking, some dishes may lack flavour, but some extra preparation steps can be worthwhile.
Though it isn't necessary to brown most meats first, flavour is often enhanced by browning, and fat is decreased. Dredging meat or chicken in flour, browning, then deglazing the pan with wine, a little vinegar, or broth and adding that to the pot can make quite a big difference in flavour.
For the best colour and texture, minced beef is best browned before using and excess fat and liquids drained except in meatloaf or other similar dishes.
To simplify preparation, purchase large packs of mince beef, brown, drain, and freeze in batches for your crock-pot meals.